RE: Fuel tank on CG
Striker,
Sorry I missed your request, but the question is a little difficult to answer since I have never flown the plane *without* the tank on the CG! Also, this is my first 3D plane so I am not the best person to ask how much 'better' it flys.
As for balance, mine is currently a little behind the recommended CG without any additional weight. You might notice that my battery (1650 Nimh) is strapped to the former just behind the trailing-edge of the wing. I cut a small hatch in the fuselage about halfway back to mount the RX (and eliminate the need for extensions on the rudder/elevator servos-- the ailerons needed them anyway!). I had planned on moving the battery back but have been advised against it (too much mass in a weak part of the plane... something that I agree with now).
I am running my YS on Powermaster 20/20 and the plane goes like a rocket (and I am only on my 2nd gallon... still lots of smoke). Can't say for sure how the Saito will pull it, but I'm sure there are many others here who could!