lus1: that's basically how I do it as well.I balance my rims using the axles of the bike and two jack stands. Put the axle through your rim like it would be if it was on the bike and use the two jackstands to hold the rim up off the ground by sitting the ends of the axle on top of the jack stands. Now give the rim a light spin. As the rim slows to a stop it will actually stop spinning in the direction that it was going and start to rock forward and backward on its axle before it stops. This happens because the heavy part of the rim will always end up at the bottom.
Mark the rim at the very bottom with some masking tape and repeat this step a few times. Each time the rim should stop in the same spot with the masking tape at the bottom. This is the heaviest section of the rim. Now you have to add weight to the opposite side of the rim directly above the heavy spot to balance the rim. I usually start with between four to eight ounces of weight and then give the rim another spin. If the rim is balanced it should now stop in a different spot every time and not rock foward and backward before stopping. If it does not then continue to add or remove weight until it does. Now for me this is more than accurate enough to get the job done and extremely cheap to do. Some will agrue that is it not but I have done it for years and never had a problem with it. So if you are looking for cheap and easy it doesnt get any cheaper or easier than this.