I have used the PS1 namco guncons and saturn stunners on my PVM no problems.
For PS1 I bought a gamestop off-brand component PS2 cable that has both component and composite. The PS1 outputs RGB on the same pins the PS2 outputs component on. You have to add 220uf caps to the R G and B lines, negative side toward display iirc. Then just use RCA to BNC adaptors, cheap as shit on monoprice. The composite line can be used for sync, you may need a lm1881 depending on monitor. Some PVM's take composite video to EXT sync with no problem at all. I just piggybacked the guns into the RCA for composite video before sending it to the monitor with an RCA to BNC adaptor.
Sounds great! Thanks for the answer. I still need to get a CRT and have been checking Craigslist for decent Trinitron/Wegas and PVMs (barely any) so I haven't decided whether I'll be going SCART to Component or SCART to BNC for my Saturn/SNES. I didn't even know PVMs were a thing until recently.