We also have a davit from Nick Jackson Co, Redmond, WA. It's the Low Profile, 1000 lb system. I called the company last spring to ask a question and Nick answered he phone. I'd recommend the company.
Only time I've ever towed a dinghy was on charter boats in the BVI. On a short haul it would go in the davits with the motor, longer stretches the motor came off and was mounted seperately.
The Nick Jackson units look good. I've seen several on boats in this area. They have a picture on their web site showing one on the front deck. That would be my first choice rather than all the way up on the hardtop. Need to check if there is a local installer.