you have lug centric wheels vs hub centric. need special adapter to properly balance tires. find shop that has a
Hunter Road Force gsp9700.
Hunter Wheel Balancers and Wheel Balancing Accessories - Hunter tire equipment improves overall balancing results, saves on wheel weight costs .
Just start googling 4runner shimmy wobble vibration and Road Force balance. This is a 'known' issue unknown by most, including most dealer service departments. Hunter website has a shop locator top middle of page. The combination of a Road Force balance plus the Straight Track process (where the machine compares all 4 tires and determines on which corner of the truck each wheel should go) absolutely solved my vibration and tracking issues.
I had a vibration which felt like an out of balance front tire. I knew it could not be an out of balance tire issue because they had been balanced twice in the past year. This was wrong. It was exactly what it seemed to be, an out of balance issue. I did Google google google = T4R posts about this issue = lug centric vs hub centric = Hunter Road Force gsp9700 tire balance machine. No more shimmy wobble felt through the steering wheel at various speeds. That combined with the Straight Track process made an astonishing difference. Astonishing because the problem is fixed. I drive along with a vibration free steering wheel and the truck tracks as straight as straight can be. It is joyous thing.
I replaced my radiator fan because it was warped after 180,000 miles and caused a noticeable vibration.
I will replace my transmission mount when the part arrives next week because my sagging transmission = misaligned drive shaft = mechanical roughness/vibration @ 2300-3000 rpm. I should be as smooth as smooth can be with new transmission mount. I'll let you know.
3 vibration sources: 1) out of balance tires, resolved. 2) warped radiator fan, resolved. 3) sagging transmission/driveshaft, to be fixed next week.
I went to a Les Schwab here in Denver I located via the Hunter website, which you may find helpful in the future.
(oops, didn't read entire thread. was replying to your initial post, thus the long thing about my lug centric journey. My other two fixes may be relevant to the tiny vibration you still feel).