Quoted from Turboderf:Black Water 100 is a real pain in the azz
I've done one of these myself, and all of the gates and spinners on the upper level are connected down to switches underneath the main level with thin wire tie-rods. Of course each one is unique, so keeping track of their placement is a bee-otch!
Add in the fact that most of the playfield is covered with thin, easily breakable vacu-formed plastics, and you've got a perfect recipe for intense aggrivation.
Later,
EV