What Brachypelma species am I looking at?

Brachypelma hamorii most likely although I don’t know the difference between that and smithi. Miss mine

B. hamorii by this photo

What do you look for to tell the difference between the Hamorii and the Smithi?

smith typically have more orange on the second patella and are brighter on the first, and the color tends to wrap more while the red on a hamorii is more of a patch. Hamorii tend to have greater color breaks on the carapace. In your photo your carapace looks more like a smithi, but this is one of the lest consistent tells. So try to get a decent close up of a leg. One of the best tells is hamorri in the red patella will have a small black triangle at the top. So if your photo is lacking color, perhaps those lower patella are orange, versus buff, then it could be a smithi
This is your best primer, go to page 2. https://arachnoboards.com/threads/b-hamorii-vs-b-smithi.319678/page-2

I tend to circle back to a few posts by Exoskeleton Invertebrates and @The Grym Reaper, who also reference trochanter color. Not sure if I'm allowed to post comments by them but even if you Google "arachnoboards smithi vs hamorii" the top result regarding care summarizes the differences. The aforementioned legend has a few detailed posts with pictures if you care to stalk his profile.

I'm "camping" right now but can circle back if you can't find it

not sure if any visual differences can really be used to determine the species for sure

get a molt, cut out the spermathecae, flip it over and then look at it under a proper microscope

you can then compare it with the spermathecae in the recent revison of the brachipelma genus