We use an 8hp Yamaha 4-stroke on a 24' fiberglass rig(very heavy boat with a hardtop) and it works great at pennies on the dollar compared to the 225hp Yamaha
Did the holiday copme with a kicker bracket?
Cheapboatkev's '68 Holiday did and it makes it a perfect height for a longshaft kicker. The size all depends on just how cheap you want it to be in case you plan on trolling all day with it routinely, that's what we use it for.