After several years of ownership I have just started to ride my giraffe. It is a 5 foot DM, the big heavy solid twin chain beast.
Doing better than I expected, because I am a very timid slow learning unicyclist, and the height does still worry me. However I am not really happy with the seat. Tried a couple of different ones, and am presently using the standard seat off a yellow 20 inch ringmaster. I have the seat slid so as to be tilted as far back on its adjustment as the slots allow. It cannot go any more nose up. But I still feel like I am likely to slide off forwards. This may be, and probably is, a lousy technique problem. Should I give it more time? I have only ridden in total a couple of hundred yards on it so far.
If you’re feeling like you’re “likely to slide off forwards” I suspect it has a lot to do with your posture. Are you bending/leaning forward with your upper body? Is the uni slanted way back when you ride?
If so, try sitting up as straight as possible, this should make the uni frame much more near vertical. For practice, exaggerate by pushing your hips as far forward as you can. I don’t think you are balance over the giraffe.
Also, Unicycle threads like this should go in RSU.