What kind of airplane? The G pull really doesn't matter. You can do a 2.5G
loop in a Pitts or Extra, or a 7G loop. It's all a matter of finesse and
feel.

People will talke about easing up as you slow at the top of the loop, but it
kind of depends on the plane as well as your energy and speed.

Really, the best way to tell would be to get a ground instructor to watch-
otherwise, you could practice a million loops but they could all be wrong.