I completed the installation of the Bigsby on my Epiphone Sheraton II and it is gorgeous. Pictures attached. You have my permission to use these photos for promotional or other purposes. Interestingly, the tailpiece studs were the same diameter as my 1999 Sheratons. The new ones were a little longer and had better fitting threads so I went ahead and used them. The Gold was worn off the top of the old studs anyway so the new ones look better.
I am so happy that I found your products. When looking at the Bigsby web site, they recommend the B-3 for the 335 style guitars. I could tell that the B-3 was way to short for these guitars and the handle would not be easily reachable. Your recommendation of using the B-6 with your replacement hinge plate makes the B-6 the perfect vibrato for the 335 style guitars. No other web sites made this recommendation.
The Towner Down Tension Bar is also the perfect device to use with the 335 installation. Not only does it eliminate the problem of what to do with the old tailpiece stud holes, it completes the necessary grounding of the strings. The 335 style guitars ground the strings by an electrical connection to the treble side tailpiece stud. Without physical connection between the strings and this stud, the strings would be ungrounded and be subject to electrical noise.