RE: Hanger 9 Alpha 40 trainer with a Saito 56?
I've instructed on an Alpha 40 with a Magnum .61 4c and it had more than enough power, so a Saito .56 will be ample power. All the Alpha's I've had or worked with have been nose heavy with a 2c, so a 4c will require shifting weight back to get it to balance. It also flies a lot better with the CG towards the aft limit.
I also have an LT-40 ARF kit waiting its turn on the assembly bench. It'll be powered with a Magnum .52 RFS, which is very good, dependable engine. The last LT-40 I assembled had a Magnum .46 XLS and required several ounces of lead in the nose to balance leading me to think the LT-40 will be great with a heavier 4c up front.
Either plane will be excellent. I do know that an Alpha 40 can be set up to be very aerobatic and will do most (but not all) the maneuvers a Stick will do.
Hogflyer