I know several people have suggested having sinks that are 8 inches deep... I have a commercial ( $149) ABS sink that is around 5 deep and I think it has advantages at that height. #1.. if the sink is 8 inches deep, you have to reach DOWN 8 inches to reach the bottom and do anything. Are your arms long enough? Do you have a bad back that pains you if you have to reach down for long periods of time? Why not make the plywood sides 8 inches, TRY IT OUT DRY, un nailed, and un painted, then adjust as needed??? The way I use my sink is to use the top lip as a leaning bar, and my wrists and arms reach in and slightly down to get to the trays. If the drop to the bottom of the sink is too much. I would need to reach down too much and makes my back sore. You are worried about splashing over the lip and onto the floor? Even 3-4 inches is enough to protect against that. The water does not splash up very easily.. It splashes out and down. Cutting down a too high sink should prove fun.. I can not imagine trying this with a saw ( circular, skil, table, reciprocating or hand.) You will get rough edges that will make you miserable. Best make it right the first time... It is your sink, so make it your way.. But too deep is not my recommendation.. Frank Filippone red735i@xxxxxxxxxxxxx