Thast may be the case in the US but is agianst our wiring code in UK.
Current in a wire causes heat. The higher the current, the more heat. All cables exibit a voltage drop when passing current. Watts = volt drop x current. If this heat cannot escape, the temperature continues to rise...
I Would put your drywall (or sheet wood) on top of your ceiling beams. That way they're available for mounting lights and other items. They're also useful to hang things from when your walls are full. Storage is always a problem in workshops. To quote a wise man, "Space, the final frontier"
BTW...
A timber frame with removable roof and sides makes maintenance easy. Here in UK we use Yorkshire boarding on agricultural buildings. Even the single layer keeps the rain out remarkably well while still allowing ventilation. It also cuts down sound too. If you make the wall nearest your neighbour...