Jeff --
I've been looking at trim tabs since the first day I had my 16 Cruiser in the water in May '03. Boat is fine with two aboard, but with 1 or three, or if that second person moves a little the boat goes out of lateral trim very fast.
The boat is so butt heavy (seats are a full 2 feet aft of the 16 Angler's position) with engines, fuel, and battery on the stern that getting the bow down to stop pound in more than glass smooth water takes more than just power trim. The Honda-packaged SST hydrofoil does this part very well, but has so much lift that turns can get a little strange.
Why C-Dory put the battery to starboard is still a question, and placement of a kicker engine there makes the boat heel to starboard even more. I don't have a kicker mounted and won't until I can find a way to trim the boat back to level.
By coincidence about 10 minutes ago I had 8"x10" templates cut out of cardboard and tried them on the stern of my 16 Cruiser. They looked VERY big holding them in my hand, but not so bad on the back of the boat. This size matches the Bennett M80 sport tabs I'm considering. I was concerned they'd interfere with the swimstep -- we tube enroute many times. But the seem OK.
Measuring the pistons I noted I'd have to cut out part of the swim step. Is this cored? I think I can just pull it off, grab a big hole saw, and remove enough material for the top of the piston.
Looking forward to reading the responses before making this change.
-- Chuck