Cool. I ordered the new board and am going to use it with the 5670 first. But I have bought so many 7N7 tubes (yes, I have a problem) that I am seriously considering converting them over to 6SN7 and then using an adapter to be able to use the 7N7 as well. It will be a while before I am able to do that myself, but if you get around to it do post how it goes. We'll see who gets to it first! If it is just a pin-out change to the new socket, and I can ask Grainger about the bias trimmer, I may go ahead and have a shot at it once I am comfortable with the sound of the 5670.
I have some very large auricaps dangling from the bottom of my Paramounts as well. Plus some teflons, and I want to put in some oilers in the power supply, and...