If you are building a LR hunting rifle then I'd go with the .270 Win 1:9 twist 26", and try some Matrix bullets
or the new LR Accubond when it arrives on the shelves. There is nothing wrong with the 6.5-06 and I had one for a short time, still have the dies. I may go back and revisit it later. I just felt that the 6.5 didn't offer anything special over the .270, and I could always buy factory ammunition in a pinch.
I'm assuming this will be built on your RAR action, correct? Are you going to build a new stock for it as well? I can't imagine the original stock holding up very well with the added weight of the heavier barrel, even with the fore end reinforcements you did. I'd probably order wood stock from Richard's Micro Fit and with your milling skills build an aluminum bedding block for the action and run it as a single shot.