To be honest , I can not recommend any 2 stroke bigger than a .47 , thats all I`ve used as far as 2 strokes. I do have a ST .90 in a new 4* yet to be flown and am starting a CG Sukhoi .90 with a ST G 2300 .
I would think an O.S .75 would pull it pretty comparable to the Saito 1.00 A lot depends on how the plane is set up and how much it weighs .