I have an iPad Pro with a P3 display color space, so I wanted to see how it compared to Adobe1998 and Pointer's Gamut. It turned out to be fairly difficult to find, and confusing, as usual. I discovered that Standard Object Color Spectra (SOCS) has replaced Poiinter's, which was established 37 years ago, because new dyes etc have been developed since. In one of the plots I saw SOCS appeared to be slightly smaller than Pointer's. I was able to see that P3 is adequate to cover SOCS and is a little bigger than 1998. This may help as search term
Pointer_MacAdam_Wide-Gamut_Displays_v2
I can't find the reference that showed SOCS to be slightly smaller than Pointer at 50% luminosity, but I saved the search page and will try again.
This probably isn't too exciting, but it led to some interesting reading and the possibilities of six primary displays.