Cheers Joe ( is it Joe with an "e" or without?)
Yes, the wheel speed did seem slow, but as you say, I think the large wheels will mean a faster ground speed. Although, I do prefer to drive them scale like, if that makes sense, ie slow.!
Ref batteries, I think its designed for 12volts, or at least thats what everybody seems to use.
Depending on room in the engine bay will determine what type of battery I use. I've used Lipo's in the past, but I've noticed a new battery on the market, Lifepo, they seem to have a large capacity for a fairly small size and they're voltage is very similar to Nimh
I prefer to build it prior to painting, so I can ensure everything fits before painting. I used to be a measure once, cut twice kind if guy, but having had to do everything twice, I'm now a measure twice, cut once