UPDATE!
It's been about 9 months since I started this thread and I appreciate all of the input. A couple of weeks ago I put on a set of Avon Cobras. I had used them on my Valkyrie and got good service from them so I figured "why not?" give them a shot on the "6" also. I only have about 800 miles on them so not much to report. I had about 16.5 K on the OEM 'Stones and and they weren't done yet. I just wanted fresh rubber in case I woke up some morning and decided to hit the road to somewhere.
I just put a set of Avon Cobras on my F6B as well. They have been excellent on my 2 old Valkyries so I figured why not give them a try. I did wear out 4 rear/3 front of the OEM Bridgestone tires and liked them just fine. My only minor complaints were that they squirmed around a lot on tar strips, and they didn't last as long as I expected. So far I'm very pleased with the Avons.
I have had great luck with Michelins in the past on an old BMW. I like the idea of a 65% aspect ratio as a little bit more cornering clearance would be nice. The only thing that would hold me back is the bias ply construction.
I'm running Avon Cobras but would be happy with E-4s also. I have a Yamaha Venture which runs bias tires and no problems. I would not mix a radial and a bias front to back. Do not see much advantage to a 65 over a 60 series tire. What is that less than a millimeter?