Greg Meyer would be the best to give advise on this, he fishes with minners, blood suckers and dirt turds (worms) for Walleye. He runs tin but has more intelect than most "eye" fishermen:lol::lol::lol::lol:
Ahhhh Toxic... You are a loveable old arse...:lol:
The mounting plates for most downriggers are "flat" on the bottom... So the first thing you need to determine is if you would have a flat location on which to attach the baeplates... I know that on some Ranger hulls the owners epoxied small squares of plywood under the surface of the boat to give some additional support. D'riggers are heavy!
Also, there are some auxillary plates that attach to towers that might be easier to work with (although obviously an additional expense. I will look into a source (catalog) for those so I can post it here...
I will also check with my mechanic who does do some big water boat rigging...