The other day I finally got the last of the work on that thing done. It's pretty needlessly complex in places, and I had to do some modifying and hammering to get everything to go together. Finished product with the freerider bars looks like it should be ridden by a wild-eyed guy in Victorian clothing and a leather WWI airmans helmet ranting about saving the future in his time machine. =) But it works. If I had to do it again, I would not have gotten a conversion set, I'd have gotten a finished product that wouldn't upset the bike shop. Lots of grinding, hammering, and other nit picky changes to the structure of the bike were involved.
I was able to ride it immediately - it took two blocks to get used to the steering. I suspect that's because my other 'functioning' bike is a road unicycle, and as a result I'm much more accustomed to spinning without yanking handlebars around. The handlebars actually aren't even what you use to steer the thing for the most part, rather odd but no trouble after riding around with no bars at all. I can already tell that i'll need shorter crank arms.
Any suggestions on how far I should try to be riding and the like for the first month or so? I've been off of bikes for a couple months because of this damned hand injury, and weather was making unicycling a bit dangerous until very recently. Slick tires plus ice and snow and debris scattered everywhere are probably a bad combination.