I like a little extra power but I think a 75 2-stroke in a 40 size airframe is too much. I would look for a 60 size airframe.
It seems like the GMS 75 and the GMS 61 engine are the same weight and size, the 75 is just a bored-out 61.
Horizon has really thinned out their plane selections but I would look at a few models from Seagull. Seagull makes good planes for the price...in my opinion. Look at the
Christen Husky 60, ,
Glasair Sportsman 75 ,they also make a Decathalon and a Cub in a 75 size too.
If you can find a Beaver or Taylorcraft in a 60 size they make good float planes too
If you want to have some fun ,get a
60 size Stik on floats
One of my most stable and scale flying planes is an older SIG Kadet , but that was a kit. If you can find one already built that would be a great choice too.