[RoyMercer]

"My guess is that it will sound better in that configuration vs. different."

I wonder if a different amp / pre-amp will effect surround sound just as not timber matching your speakers will?

"My bigger concern from running the 2-ch tube output for movies/surround would be the extra time on the tubes when it's not really needed."

I would not be as concerned with this as I would using my main amp. The pre-amp tubes will last a lot longer. I have played my Luxman CD player thousands of hours since the middle 1990s. The last time I changed the tubes was in 1995 and they still sound fairly good. However it does have a pre-heater that will extend the tube life and like you said, not really needed. I can't see tubes making a movie sound track sound enough better to warrant the tube wear. Especially if we are using expensive NOS tubes.
Maybe MCH SACD and / or DVD-A...

I went with the tube mod and all out SS mod. Still teetering if I am going to spend the extra cost for the Bybee rails.

You guys are absolutely correct on one thing, we will soon find out. I feel like a kid waiting for Christmas! It will be interesting to hear others feedback using different amps , speakers, etc.