3Ah may be a little OTT for a single fight, but if you can afford the price and weight then go for it. It helps greatly at live events unless you have a few sets of batteries because after every battle with 2Ah your batteries will be dead, this was my downfall and now im currently running 3.3Ah Ni-Hms, put them back on charge after every fight and i can get through an event without the need to change them.
Drill motors will be better if you can, and yes plywood is good, take a look at Bernard, they just cover their Plywood in other materials.
Grant