I have not tried mixing, and I also like the PR2 fronts better than the PR4. However, you might have better luck with 42 pounds instead of 39. That seems to be the common by a number of people.
You say the head shake is still there. I bent my rim last year and had to get a new one. The new one was not bent but it was out of alignment, so it would have a wobble when spinning. Lift the front tire and give it a spin, see what happens. That's how I noticed mine after installing it. A...
I'm going to take a day or two to get to the RR, but can't get that much off. I will be doing a straight shot home on Sunday. Maybe we could ride back together. A lot going south, so I'm sure you can team up with someone.
They are not the GYTR version, they are the newer Y series, although I'm guessing they are the same, but different branding. I got mine for a lot less, $800. Still expensive, but you can't take it with you, so enjoy it while you can.
I rode the Quincy to La Porte yesterday. It is open all the way. I had zero cars in front of me from Quincy to Marysville road. That is 65 miles of curvy heaven.