I recall hearing he used a Fender Harvard amp as a practice amp. The story I recall was that he got it at Scottys Music in St.Louis.
http://www.ampwares.com/amp.asp?id=64
I wanted to buy a Princeton Reverb the other day, but instead I lugged the DSReverb Head up to the computer room to compare with the Danelectro, using the same 10" speaker/cab.
Obviously the DSR sounded better to me, but honestly, at this low volume, they really sound quite similar to me.
I end up playing electrics "unplugged" around the house as well, but I need that "one-full-notch-up-from-unplugged" to play along with the Boys, especially with the Mu_III/Octv material.