Looks awesome! Wish I had the gear to do fingerjoints.
BTW, if those 6J7's are wired as triodes, then they will have a fairly low amplification factor -- this amp was designed to stay clean all the way up the dial after all.
If it's not, then I would personally rewire V1 as a pentode. Done right, it should turn into a real screamer without having to change the tube complement or anything else!
(It would be a shame to hack this amp for 9-pin tubes, IMO.)
- Scott