Actually, my fav. combination was putting a pair of NOS 6H30's in the Moscode...
I used to run them in my CJ ACT2 with excellent luck and also have a pair in my ARC SP-17. The NOS 6H30's are a little spendy, but in every situation I've tried them, they retain the punch that tube is known for, but reduces the grain and takes away the ever so slight edge that the standard issue EH 6H30 has.
The really cool thing about the Moscode is that it is probably the easiest power amp to tube roll and you can get a wide range of sound, depending on the tubes you select. This makes it really easy to dial it right in to your room, speakers and the tonal balance you prefer.
Definitely one of my favorite power amps of all time... Awesome performance, easy to customize and reasonably priced. And the guys at Moscode are very nice as well. Designer George Kaye is always fun to chat with....
Hope it works out to your liking...