After decades on wide 6-strings, i'm very used to 19 & 20mm spacings. Most narrower spacings feel like a darn fiddle at this point. But a gig's in the offing that may require a P bass (which i started on, back in the Paleozoic era). i got a nice Squier VM Pbass (I measured the bridge & it looks like approx 17.75 spacing), but the amount of fretboard left & right of the strings makes me wanna start modding. Thinking of a brass nut blank to slot slightly wider, and a Hipshot replacement bridge I can roll out to 20mm. I know that wide spacings aren't overly popular around here, but I was wondering if anybody's ever attempted the same thing.
The mods will net poor results. You will gain little. Get a US / Mim. Get a Warmoth or the like designed with 19mm spacing out of the gate That said the nut and bridge are easy mods, The bridge will be a bolt on, the nut is an easy mod if you will cut it yourself. You won't gain a full Mm at the nut. The pickup poles will likely not line up, but that's not a big deal overall. My 2¢