Ken, I appreciate you stroking my ever-expanding ego, though my wife would disapprove.
The main thing I try to stay away from in my building is introducing tension into a bass' corpus. All my basses are a little asymmetrical because after I build the rib structure, I let it relax, and then match the top and back plates to it, rather than doing the opposite, which is more common. I look for good, stable, well-seasoned wood. I stay away from common blunders I see in basses I repair, such as ill-fitting or crooked neck joints, and plates that don't meet the blocks. The workmanship you don't see is more important than what you do see.
To answer your second question, I would say a few hundred.