Not directed to the OP specifically

:
The tailpiece of some violin basses (e.g.
Invalid Link Removed) is shorter than those mounted on Hofners, making the required string length longer: I remember a post by a user who'd bought a Pyramid set that didn't fit (strings started tapering before reaching the nut) on his particular Beatle bass copy.
I guess one could replace the tailpiece with a really short one and use regular, long scale strings (not medium).
Also, one could get creative and create a new attachment point for the lowest(s) string(s) further back in the tailpiece itself: for example drilling a hole/holes in the small plate connected to the hinge (provided said plate is lifted from the body, leaving a little clearance), thread the string(s) into it top-to-bottom and then into the regular tailpiece hole(s). This way (super-)long scale strings might fit just right (obvious caveat: measure twice, drill once).
Alternatively, one could try soldering little metal eyelets to the tailpiece at an appropriate point, in order to create enough extra afterlength for long scale strings to be used. With roundwound strings it's really a problem for the E and maybe A strings only.
(By all means disregard if part or all of the above sounds too janky-arse.)