Best riding SeaCraft model ?

[76Red18]

Prop might be losing it's bite. You say the engine is 3" high. I would lower it a hole and see what happens.
As far as proper trim, that depends on conditions. With my 18 in rough water, where I need to stay below a certain speed to keep the hull in the water(15-25 mph), I pretty much have the engine trimmed in and use the tabs to keep the running surface as level as possible(best ride). In really bad conditions(below 15 mph), no tabs and use the engine trim to keep the bow from stuffing. When I need to speed, I peg the throttle, trim the engine until there's a little prop ventilation, bring the trim down a little, then use the tabs to stay level and pick the whole hull up out of the water a little bit more. Might need to bring the engine trim down a little more.

As far as best ride goes, I bet Mr. Moesly would say to keep the running surface as level as possible regardless of how much of the hull is in the water.

A 4 blade Bay Pro III prop would do wonderful things for the ride characteristics of a 20 with a heavy motor on it's arse...