If you are using a Saito 100 in the Funtana 90 you would be smart to install a pull pull. Check the HUGE Funtana 90 thread in the ARF forum, there is a lot of info. Guys that didn't mount the rudder servo on the CG with a Saito 100 had to mount their batteries on a stick forward of the firewall inside the cowl to get the plane to balance. According to those that are flying theirs now, the recommended CG at 7 1/8 flys tail heavy. Most people are setting the CG at 6 3/4" from the leading edge for the maiden flights.

I have a YS 110 in mine with Hitec 5645MGs all around except the throttle. I mounted my rudder servo on a pull pull and it balanced at 6 3/4" with the reciever up front and a Fromeco 2400 Mah LiIon mounted just behind the canopy. I should get the maiden flight in on Sunday.