1 ElectroTastic 7 months ago Okay, Let's get the "under or over" discussion out of the way first....Factory Prototype Jet or not, the B7 tension roller on my 6129T players edition is giving me tuning instability and a pretty dull vibrato.I could live with the tuning instability for a while, but in the last couple of string changes, it's starting to get my goat. fwiw 10-46's if you were going to ask.So perchance / mistake / inattentiveness found me having half restrung the bigsby without running the strings under the tension roller this morning. I just wasn't paying attention.Damage done - eh whatever, but lo and behold.... the damn thing is bang on in tune, AND stable. Not only that, but the vibrato spring reaction / sensitivity is almost as good as my Duesenberg. In other words, it's just about perfect.Now I know this is not a new idea, but I did want to dot some i's and cross some t's off before pursuing this a little further.I've come across 'biggsfix' offset tension roller for a B7 bigsby - and I am wondering if anyone here has fitted one, after perhaps stringing over, rather than under the tension roller. If you have one fitted, could you please advise the following: can the tension roller height be set / adjusted or is it located in one position only? what is the diameter of the tension roller (i.e. is it different to the factory Bigsby roller) and what is the offset from centre? I ask this in advance, as I am not certain that an offset tension roller would be the 'cure' for this particular instrument, but I am curious whether or not a smaller diameter roller or smaller offset biggsfix roller may be beneficial.The thing is, the breakover angle is actually quite respectable with the strings under the tension roller. With the strings over, the breakover is like an old archtop and trapeze tailpiece, minimal at best.Strings aren't jumping out of saddles like they were famous for on Jazzmasters, but comparitively speaking, the jazzmaster fix was a staytrem bridge with correctly spaced and sized roller saddles.I would like to have a fraction more breakover angle, but I don't want a tension roller that sticks out like dogs bollocks, which the biggsfix appears to do on some of the images I have seen.Any other advice on possible spring selection or changes would be appreciated, if you run your strings under the tension roller. cheers!