Jim

I have YS 63, you cant get the tank right on the cg.

Pull it back as far as it will go... i.e. up to F...4 ? the one thats at the lead edge of the wing.

I use a SLEC Maxi 9 0z and it fits nicely. This brings the back of the tank close to the cg point so its a better set up that many models allow of this size..