I totally get the point and agree that you should be good in riding 26" first. I had to learn the rolling mount on the 36", so further training of the idle mount on a 20"-36" did not help me. But ofcourse the 20"-36" idle mount skill is a good prerequisite to show that you are ready to learn a new 36" mount.
Crank ratios:
36"/150mm ~ 26"/108mm
36"/165mm ~ 26"/119mm
I guess for me 26"/108mm wouldn’t be easy to idle mount, 36"/150mm is like riding a bicycle, even idle mount works (also not that easy). Idle mount- rotating backwards does absolutely make no sence for long distance riding.
On the other hand you certainly have no problem to ride and mount 29" without additional skills. For cruising with bicycle riders/ the family a 36" with short cranks is possible (I don’t like high cadence), g36" is my choice and a g29" would work as well.
you’re not supposed to remember everything I write !!!
Everything from 26" and up has 150mm on my uni’s. The trials(19"), freestyle, freewheel (20"), 16" and 24" have shorter cranks.
I had been wondering if mounting the 36" would be easier to static mount, but instead of riding away in the same move, first hang on top and make a small hop, which gives enough time to get your balance point in place to take off.
To be honest, since I got the inner tube replaced 3 days ago on the 36", I haven’t taken it yet for a spin. 3 weeks ago I was trying to get the feel of the 36er again, which I find kind of scary because it is so big. Instead I’ve taken the easy way and ridden the 24".
I’m thinking of getting the Nightfox soon. Then I will understand all of y’alls talk about 36ers
you might have to wait a bit til you’re a grown up. The wheel prolly still reaches to the top of your head right now. 
100% agree on the free mount part, mainly because that thing is so high. And of course shorter cranks (or a geared hub in high gear) make getting in motion a lot harder. But…
I’m currently riding 140s on my 36er, constantly pondering whether I should switch back to 145s (because those 5mm make mounting decidedly harder). With 145s (and 150s) on the 36er I’m perfectly fine, just not on crowded sidewalks on a saturday during pre Christmas shopping madness. On the other hand I switched back from 100s to 114s on my 20er for now…
If we look at the total gain ratio I’m riding the 36er at a TGR in the 3.15 to 3.27 range, while I kinda struggled on the 20er with a TGR of only 2.54. This tells me a) that the TGR is not as easily transferable between wheel sizes as one would assume, and that b) your conclusion is a bit problematic. I can safely say that at my current skill level sub-110mm on a 26er is nothing I would even consider, but I’m happily riding my 36er - sometimes even in the city.
What is the recommended crank length for a 36er?
It is indeed a bit of a category of its own. Partly because of the weight of the wheel, but also because of the sheer height and the high speeds (for a uni) that can be achieved.
Depends who you ask and what you wanna do with your 36er.
I ride mine with 140mm cranks at the moment, though 145mm suit me better, particularly for mounting. Remember, shorter cranks force you to raise the seat accordingly. Thus, first you have to hop higher to get on the uni, then you have more difficulties to get started because of the short cranks.
Of course you’ll need longer cranks if you want to do some hill climbing than if you ride on flats exclusively.
Yes, a 36" uni is high for short crank users, as we all seem to be:
The seat height depends on the leg trying to touch the pedal when it is on the lowest pedal position. With a crank length of 36"/2=18" the seat position has to be lower than on most common 20" unicycles, or the foot can’t reach the pedal.
For really long cranks a common 20" is higher than a 36". Shorter cranks make a unicycle effectively higher and height makes them less easy to mount too.
I don’t understand your reasoning, or the numbers, but I agree on the end result: Shorter cranks mean a higher saddle. Thus a big wheel uni with short cranks is harder to mount than the same uni with longer cranks (as long as the saddle to pedal at 6 o’clock position distance is the same for both).
Exactly 
I wanted to say something about having my 150s, but I still find it hard to mount the 36", so I won’t say it
Most of the time I’m riding 125mm on my 36er. I can freemount it pretty consistently using my standard static 3-9 o’clock mount as long as I’m not doing it in the wind or on an upwards incline. 100mm cranks is a bit of a different story, I can’t mount nearly as well when it’s set up with the shorter cranks. It doesn’t help that I haven’t learned other mounts other than the static mount 
One of these days I’ll have to practice some of the more “dynamic” mounts (rolling mount, jump mount, etc.) and see if I have more success with those on 100mm cranks
I only seam to use 2 sizes of cranks on all my own unicycles. 89 or 150. I regularly ride 20", 24" Muni, 26 Muni, 27.5 Muni, 29" Muni and 36". All are 150 except the 20" and 36".
And by the way… I ride a 50" penny farthing with either 89 or 100mm cranks on it.
Caveat: Roger is not the average unicyclist… nor the average Penny Farthing rider…
I see what you’re getting at. I think TGR is most relevant for comparing speed.
As to the wheel sizes. Yes, everything is subjective and a not so skilled rider might have problems riding 20/89mm while being able to ride a 36" with 150mm. I would sum it up like this. The larger wheel is progressively more difficult for
mounting and can remain difficult for mostly not crank-related activities like hopping, jumping, bailing, crashing and wheel walk.
Control with short cranks can be achieved with practice and skill, but the 36 will always be a 36 and if I’m in a high pedestrian zone then it can be sketchy. If nothing else, just due to the space required. Even with longer 150 cranks you still need lots of space even to dismount (I once had to make an emergency stop riding on a path as someone blocked my way and I came to a full stop and dismounted to the back: and basically sat on the wheel and handlebar of the cyclist behind me who had left only about one wheel length, which is generally enough). Another time going up a steep hill I almost landed on the rear bike rack of a cyclist as I was pushing hard to keep going and the cyclist barely made it and stopped at the crest of the hill. At the last second as I was being catapulted forward by momentum, I was able to throw myself to the right and landed next to the bike. On the 20 I would just step off and grab the uni by the saddle and swing it out of the way.
I rode the last few days 20/29/36 keeping this in mind: on the 36/125 commuting I have to concentrate to do my static mount (if I’m tired I may miss), but on the 20" I could mount in my sleep (and can do reverse leg mount, jump mount, mount to 1ft idle, jump to stand hopping, etc.). On my 29 muni with 110s my static mount is also super solid (except uphill but that is different).
On my 29 with 110s I have so much control that I almost never worry about pedestrians or obstacles (I can also do rolling hop or static hop if need be as well as side jump or normal drops). So I can “save” almost any situation. On the 36 I find I need to plan more to not be in certain potentially dangerous situations.
To sum it up: with skill (and strength) you can ride short cranks, but some aspects of the larger wheel related to height and space required cannot be fully overcome by skill (imagine riding through a Guinea pig and rabbit cage with kids chasing the animals: with the 20" probably possible to not to run over or step on kids or animals (if not advisable) but on the 36 would be way too dangerous to even think about it.)
I think you ride more road than muni, but 150mm is just way too long for brake-assisted muni unless you’re exclusively doing super long steep climbs (I often switch to 136mm for >300m vertical climbs on my 29).
And riding a 29 on the road with 150s is also incredibly slow and aggravating.
This week I am practicing riding relatively short (20-60m vertical) steep climbs around 15-25% grade with the 29 with short cranks. Monday I made the 42m vertical climb with a >20% section twice with only one dismount each with 29/110 (2 weeks ago no dismount 2/136). It’s hard work and requires lots of balance (gained from freestyle) and strength, but is a lot of fun.