Tony,
No doubt tube amps sound sweet, but you may find that you will need a bit more power to drive the woofers. The Cornwalls are quite effiecient @ over 100dB, but power is still power. The Dynaco is only 35WPC.
I've wanted to do something similar. I was thinking a good approach would be to find a tube amp with a preamp output in addition to the main out. I could then run the pre out to a solid state amp for the lows, (As a hybrid configuration) and use the main outs for mids/highs only.