Sad it has to go back, but if it's not cutting it for you, it's not cutting it for you. I'd maybe look a little higher in the Sire line?
For a tight B, good-hardware, low-back-strain bass, I'd suggest the Sire M7. It's up a step price-wise from a V3, for sure-- maybe an M3 might be a good choice (I haven't played one but seem similar, just fewer bells and whistles, to M7). M3 also has maple board option which M7 doesn't.
M7 has 35" scale, but which is hardly even noticeable due to body size and shape and, I guess, magic; gives the B a nice, tight, smoothness. Less floppy than a V7 B.
It's sub-nine pounds, very comfortable; it'd be good for a back-issue person IMO. Has a nice bridge, and, as far as I've experienced, good tuners, though they do get turned a bit in the bag (very smooth turning pegs, maybe that's the tuning issue you reference?). I tune before every gig anyway naturally, so it's a non-issue. Stays in tune when played.
Anyway, I hadn't had it out in a while, so I gigged the M7 this past weekend. I'd forgotten how nice it is. While there's a lot of factors besides the bass itself, I thought the M7 sounded better, that night, than the Sadowsky Metro I'd brought and played first set. The M7 seemed to agree with the (borrowed) Quilter quite well.