Pondering on a Schlumpf - questions

[gkmac]

There's a distinct possibility of me breaking my new years resolution of buying another unicycle. I bought a 24" muni last year, a 6ft giraffe the year before, and a 20" freestyle in 2003.

I think my next venture will be some kind of 29er for long pavements and roads, and let's be honest... I want to go for broke and get a Schlumf geared uni.

First question (possibly stupid): is it possible to idle and ride it backwards? I'm thinking if I need to idle it in case of sudden obstructions ahead, somehow my mind says it may not be possible with geared mechanisms.

Second question: as seen in this picture the hub clearly says "please read instructions carefully, especially for off-road and free-riding". What exactly are the issues when it comes to off-road riding? Smooth-ish gravel tracks will be the roughest terrain I plan to ride it on, so I'm more curious that worried.

Third question: what size cranks do you recommend? I'm so used to the 150mm cranks on my 24" muni that the 127mm ones on my freestyle feel so twiddly and small for my extra long legs (34"-35" inseam). I was thinking about 140mm but that doesn't seem to be an option on unicycle.uk.com, so it's gonna have to be 127mm or 152mm...