I Have the 73" powered by a saito 1.80 and it flies really well. FS 200 would be awesome and it will fit ok. ust a couple of things:

make sure you use a good softmount (better with a nosering)

be very careful to loctite as many screws as possible. this plane vibrates a lot at idle in 4 strokes. when you power up, the vibration is stronger but at a highr frecuency, which is not as harmful as idle vibrations.

enjoy it! FS 200 is a very good engine