[Borobo]

It all depends on the construction of the frame. in many WCD's the belly pan is made out of diamond cut alum., which contributes to rigidity, which can become a problem especially in thinner or less sturdily constructed sheet metal or 1x1/ c channel frames. in the event that you have a rigid and strong frame that doesn't need the extra support, I suggest going with something as light as possible, such as our material of choice this year, verilite.

to address 2, I would just create something and linear pattern it however you want.

don't really know much about 3, we just lay out our electronics, trace them with a dry erase marker, then drill holes accordingly