Powerglide, you may want to consider this:
The Firestone Service Center in my area, is the only shop within decent driving distance, that has a Hunter 9000 Road Force Balance Machine.
Yesterday(Wednesday), I took my Cooper CS4's there to have them RFB'd. I will install them today to find out if it's worked. These tires(2500 miles) have had a vibration at my sweet spot on the highway. The speed in which they start to vibe, varies depending on the rotation of the tires(I have moved these tires to all 4 corners). All 4 tires were out of balance from the get/go, the Tech said...even before removing the stick on weights!
I have had these tires rebalanced several times at my installer(who I am disgusted with BTW). Again, even before removing the stick on weights, the Tech mentioned that the tires were out of balance. The Firestone Tech then proceeded to do some (whatever)measurements, looking for issues with both the wheel and the tire. And if need be, remove the tire and reposition it on the wheel which, he found nothing out of the ordinary, just the balance!
I was only charged for the tire RF Balance($12/ea) but, if there were any tire that may have needed to be dismounted/repositioned, the cost could have been as high as $25/tire(a good price IMHO).