Yeah I put the KT-77's in too. I love them, I think they're great, but I came from mesa 6l6's so its not really fair to compare them to JJ's KT's. However, they tightened up my sound, they added upper mids, so they are really much clearer sounding and the bass while still vintage and saggy is much tighter sounding, it really sounds more fenderish to me than with the 6l6's. I'm sure people will disagree with that, but those we're my findings, the KT's didnt sound marshally at all to me, could just be the room, the preamp tubes, anything really, but they make the amp sound more fenderish to me without brightening it up and making harsh, I like them more than the 6l6's in this amp. Im going to try them in my stiletto too. Im hoping to pick up a lonestar special as well, and an M9 or 400+ with a 6x10 for my bass. I've got a spector that needs work. Anyways, off topic.
For anyone on the line about trying KT-77's, they were worth the money to me, made a good improvement in my amp, I recommend them to any lonestar user.
~ PilotSSW