RE: H9 ultimate questions
No CG issues that arent helpful. It tends to come out nose heavy, and I recommend moving the rudder servos to the tail. It helps the CG and tail mounted rudder servos are better so its a win win. The CG in the manul is a little too nose heavy BTW, and fear not because I absolutely hate the feel of a tail heavy airplane.
use a 50 oz fuel tank. If noise isnt an issue a Mej 30 x 10 really pulls but howls. A Mej 32 x 10 is good for IMAC.
The battery system is good as long as the Hitec servos tolerate it. I have no knowlege there.