I have a Great Planes AT-6 Texan and added hobbico mechanical retracts to it. I have only flew it twice and both times it came in hot. I bought a C.G. machine and it measure about a half inch off (nose heavy). I am just going to move my battery back for now, my question is should I rely on the c.g. machine balance it out all at once or does adding retracts change the c.g. of my plane? Thanks, Willie.

Anything you add, or leave off for that matter, not only affects the C.G. (balance point) but the wing loading as well. The plans should show a "C.G. range" as an elipse split into four quadrants. If the plane balances in this range you should not have a problem, unless the incidence is off at the wing, stab, or both. If it is clearly ahead of or behind the "suggested C.G. range" then it should be adjusted accordingly. As for the CG Machine, if used properly, it is a good tool.

Balance your plane two ways. With the wheels down, then check again with the wheels up. Quite a few people flying warbirds have found out the hard way that the CG moves on some planes with the movement of the wheels.
Silversurfer