[jhv48]

Find a tire shop that has a Hunter Road Force tire balance machine and has a trained tech that knows how to properly use it.
I chased the same problem you have for years. Finally found a guy that mounts and balances tires for race cars using the Hunter Road Force Elite machine. Smooth as glass now.
Start here. Most Discount tire stores have the machine, but few employees really know how to use them properly. Ask the manager if anyone is an expert on the machine, if not, find one that is.