OK. Next plan of action: record a bit so I can re-amp a loop. That allows me to fuck about with the amp while having my own guitar signal as an imput at the same time. Useful, as I only have two hands.
What I'm going to do: use the best bits of both to frankenstein an über-Vibrosonic. Keep that one and faux-blackface its innards (i.e., there never was a blackface Vibrosonic Reverb model. Also, I'd like to keep the master volume.). The other one is going; I have two interested buyers. One of them has played them a lot as we've done several gigs together. Makes more sense if he gets it, I guess. I'll let him decide if I'll fix it up or let it remain in its current state. Proceeds will go towards a certain vibro champ with my name on it. And food.
Only thing wrong with that is that I really, really like the modification that has been done to the one that's going. It's been the Greeat Unifier in the several things I've called "my sound" for the past twenty years, so it'd be a bit weird to let that go completely. So I need to find out what it is first. It's an extra gain stage at the expense of the reverb. I was hoping it was the very simple mod Brad mentioned once, but alas, it's different (I should have known, as the reverb pot never controlled the distortion). It's a very usable sound, especially with humbuckers. I wonder if there's some clever way to add it to the "normal" channel of the amp I'm keeping. But it would require a lot of switching, it seems.
That must be one of those new fangled hot nails... 
