Re: ways setting tweak
There is basically two ways. One is to fix imperfections in the chassis setup (adjusting shock preload, tweak screws, etc.) and compensating for weight imbalance (adding weight in a particular area.) Generally, if you install your electrics where they're supposed to be installed, you shouldn't have to worry too much about weight imbalance. You may have to slightly compensate for a heavy servo or something like that, but you usually don't want to add weight if you can help it. You're much more likely to use chassis tweak adjustments since it's impossible to eyeball exact preload adjustments or tweak screw adjustments. For that, you will need a tweak station.
MIP, Integy, Niftech and others make them and they range from $40-100.