Well my method isn't very accurate but if the same wing drops like a rock everytime it needs weight on the other wingtip. I just picked my plane up by the prop with the engine where it turned very easy. Centered the tail wheel and the same wing dropped fast every time. I put a 1/4 ounce weight out by the tip of the light side which was close but I wound up only needing 2/3 of it. It's a stick on wheel weight and I just cut it with side cutters. Your prop should be in the center provided your engine offset is correct for the amount of right thrust.

The reason involves a 27% Extra 260 that has a bad tip stall charcteristic. Also I'm trying to break into 3D (not fast flopping but smooth fluid 3D) and it mushed one wing when put it into a wall. It's better but not fixed because most of my radio stuff is on the left side, the weight on the wing tip is a compromise not really a fix. I didn't know any better when I put the stuff in the Extra (my first gasser) But it flies good enough considering how beat up the poor things is (the fuse has been completely broken in half)

I'm trying to build the Yak as neutral as possible so it flies like it should, centralizing weight (keeping it close to the CG and the centerline of the fuse) this keeps rotational inertia as low as possible so it should stop on a dime when i stop an aileron roll. I'm even going to try to balance top to bottom. So it's will be close on the CG everyone knows and sets and it will be balanced side to side and top to bottom. (within reason)

Here is an example of how I want to learn to fly

http://youtube.com/watch?v=nbAWMFyFwZc

The are ways to check it in flight, which is probably the best way. But I want to start out fairly close to begin with.

Here is a link with ways to check everything in flight which is best.

http://www.scootworks.com/rdrc/trim.html