G'day Can't help you with Futaba info but as for servos, I would use Futaba or Hitec. There are some Chinese servos that are OK but some are not very good at all. I almost always use Hitec servos as they have a good range and they have always worked well for me.

If the plane had an electric motor, you could use quite small servos but as it has a diesel engine, the extra vibration from the engine means you need larger more robust servos. Will "standard size" servos fit or do you need a smaller servo? I have a couple of planes with small diesels and they have HS-81 servos in them. They are floaty type planes that are most definitely not aerobatic. For aerobatics, you might need to go to the 100 series or 200 series servos.

Cheers

Mike in Oz.