About fifteen years ago, I had a really fine 1966 BF Princeton, and it was indeed delicious, tonally.
I will note that, dimed, it was just about as loud as a
PR on about "6", and I found the level of breakup about the same (as in not much!). I had it modded for more gain (losing the tremelo) which made it about the same output as a
PR, and gigged with it a few times, but had it returned to stock (I liked how it sounded, but it just seemed a shame to not have the tremelo!), and later sold it during a time of extreme financial distress. I miss that amp!
If I still had it, I think I'd go with a clean boost pedal rather than modding it...
Cheers, Tim