The best stuff is at about 50 feet or shallower... Unless you are doing the Hilma or are at Karpata, that is.
For the most part the dives are all like walking down a hill. The bottom of the hill is about 100 feet where it gets flat and there is nothing but sand. The top of the hill is at about 20 feet. The reef is the hill and exists as the gentle slope of the hill from 20 to 100 feet. If you want to stop at 50 feet, you can by not going "down hill" any more and going left or right It is NOT as if the reef is at 100 feet and that is it. You can dive most of bonaire and not drop below 40 feet, if you want.
Currents are almost non existent, although some sites around the north and south tips tended to have some...