Chuck, I raised the cap to the PI to a .02 & the Volume to a 250pF. I like it, adds some Fendery bottom to it; I'll see if the intended buyer likes it, it's an easy enough swap if he likes it brighter. The Tone control is a BIT less interactive, which is nice.
So, here's the fun part, and a caution to builders: in the process of swapping the caps, I nicked one of the other caps (a Mallory 150) on the underside with my iron and exposed some innards. But I didn't see it, cuz it was upside down. So after doing my cap swaps, I turn it on. It's humming as I raise the master, and the pot is scratchy. One of my 6V6s begins to redplate. Huh. DC on it, but how? I didn't mess with THOSE caps! So I check for DC on the grids of the tubes - 120VDC! Wow!
Looking at the schem, I figure it's only a limited number of ways for DC to get THERE so I started checking for leaky coupling caps - the 2 feeding the power tubes. Both of them with 120V on the grid end, though with one of them, the voltage drops as I turn the pot. So of course, the last cap I look at, I turn it over and see the gaping hole in the side and the aluminum foil showing... replaced and all is good. Also dropped SOMEthing in the Volume pot to make it act up; a simple swap and we rock again!
New filter can (525V) is on order, along with rubber feet & more pF caps. I appreciate the lessons I learned in diagnostics, putting some of Jack Darr's book into practice.