A few other GMuni riders you may want the opinions of who I haven’t seen here yet are Ken (Gizmoduck), joemarshal, and Corbin. (I bet if you came up to the South Bay, Corbin would let you try his G24.)
Ken and Joe have said that 2nd gear is rarely useable on a 29 and often spinning in low gear can often be as fast or a bit faster. Only really usable on smooth fire roads and easy open downhills (which could build up to scarry fast speeds). Both were using 150’s, I believe, so 2nd gear would prob get more use w/ 165’s.
I’ve read where that one of the reason’s the first batch of 26’s only had clearance for a 2.6 is Kris said that when geared up, the momentum of a 3" tire would become problematic (which wasn’t really a problem at all on the 24 w/ it’s lower inertia). Also a 26x3 is nearly as tall as a 29 which would have the same poblems as a G29 Muni above.
Again I think an ideal setup would be G26x2.6 or 2.7 w/ your choice of cranks (I’d do the longer dual holes to extend flexability but they aren’t that much $ and easy to swich out so you could try both). Also that setup would prob be the most ideal for racing against 2 wheelers and giving you the best chance of beating as many of them as you can.
I think it’d be good to tweak your riding style on the GMuni to all rolling, including running into the occational 3-4 ft. drop (like in Rocco’s Wildbad vid). Shouldn’t be too much of a stretch for you since you roll a lot of the tech bits anyways. This would extend the hubs life even more.
Check out the speed Kevin gets on his ungeared 26 through this tech stuff! (yellow rim)