I will try to re position wheels 2 studs from where they are now.
I have checked the wheels for runout - rims are straight, tires have no lateral runout, but they do have a flat spot, where runout is at 1/8".
I spoke to a guy who has been doing wheel balancing for many years and has a great knowledge and experience. He said that tires that are a bit older (mine are 4 years old) and are wide and low profile tend to develop a flat spot after sitting for a few days, and it gets worse when it is cold. No matter how well you balance them or even road force balance them - you will still get vibration. He advised that I put max pressure indicated on the sidewall (in my case 51 psi) and run them for 5-10 miles - this will help pushing out that flat spot quicker. This morning I did what he said, drove 15 miles, reduced the pressure down to 35, drove another 10 miles and by the end of the trip the vibration was barely noticeable. Not sure if something got warmed up or the flat spot on the tires indeed has been reduced.