An easier solution would be trying an Alexander Equilibrium pedal.
I have a '63 Vibroverb Reissue... the 6g16 Reissue. It has bias vary trem like the Princeton has. I miss the bias vary trem when I
m playing my Silverface Bassman or my 5e3 or '59 Bassman. I went on a hunt for a relatively easy solution and checked all kinds of pedals and trem units out. The Swamp Thing is mighty nice and was on my short list. But, I found the Equilibrium and couldn't be happier. it's a bit more flexible... The Mix knob is the secret sauce. Add a little dry signal in and you get the attack of the note, and as it decays, the trem takes over. Just like the tube tremolo in my Vibroverb and a Princeton.