To follow up on this, I got the Highfield CL360 with the FCT side helm (wheel/bench assembly) and a Tohatsu 30hp outboard. Weight comes in just over 500, and attitude underway didn't seem to be much different than with the previous dinghy.
I have a 13ft whaler and a 13 ft mercury rib both have 25 hp Etec engines. Top speed in salt water is 24 to 25 knots (gps) speeds. Both weigh less than 600lbs. The rib rides better in chop conditions. I towed the rib with the whaler about 7 miles to put on a trailer. The motor on the whaler pulled the rib easily at 16 knots with a top of 20 knots with one person in the whaler (gps speeds). Towing inner tubes or double skiing would be easy. An example of what 25hp can accomplish.