The Geo-Disc certainly adjusts for any arm at any P2S distance; it’s a true universal. It does this by requiring a 1st step of aligning the disc via line-of-sight’ing its raised ridge to point directly at the tonearm’s pivot. By that step, the 1-point alignment grid swings into the correct position. Obviously some tonearms have better "center pivot" visual markings than others. And if you do something wacky, like having a way too large P2S distance on a short arm, you’ll run out of head-shell space to adjust the cartridge appropriately. I.e. the exact P2S distance doesn’t matter as long as you adjust and align for it specifically. But generally, Geo-Disc is the quickest reasonably accurate universal I’ve tried. I believe it’s a Loefgren A IEC alignment, which is fine IMO.
It works great for my FR64fx and especially Clearaudio Universal (very clear visual center). Yes, it gels with the same setting on my SMARTractor (its P2S "arm" has some play in it too, btw). I wouldn’t use it on my Phantom, but then I wouldn’t use anything other than the supplied Graham jig (or maybe a MintLP) on that arm, because the actual internal pivot point doesn’t have a good reference against the housing. The jig is really pretty nice; it could just use some minor alignment-visibility enhancements.
I could’ve been happy with just the Geo-Disc (and Graham jig for that arm).
