I don't have any experience with the Ryobi but to answer questions 4 & 5, I am using a Pro Zinger 18x10 with a G-38 and have good prop clearance. I have the servos mounted per the instructions with a 1800 mah battery attached to the servo hatch. This provided correct CG. The only change I would make is to put blind nuts in at both ends of the wing struts instead of using the self tapping screws.

John