RE: 4 stroke engine size; CBA F7 Tigercat
I have a CBA tigercat mine has G38 zenoha gas engines and it fly's great you have to look at the specs for the saito's what is the HP rating to how much you think the plane will weigh, If you build it lite mybe 150 will fly it. Mine is at 30lbs ready to fly and with two 38 swinging 24/8 props its get airborne in about 80 feet and yes build in flaps you will need them to land. no flaps and you'll need about 1000 ft to land never try to glide this plane it does not like to glide if you loose a engine dont turn into the dead engine hope this helps Topgun600