Are you asking about retail sizing in the TF9 or TF7 skates, custom or the new Catalyst skates?
I can provide some guidance for the retail TF9 and TF7 skates, but can't help with customs or the Catalyst line. I scan as a 7.5 Fit 3 Bauer (and have demoed 7.5EE Supremes at a Modsquad event in the past), was measured as 8EE on a CCM Brannock and wear 8EE Easton Mako II skates. When I tried on TF9 skates, 8W was obviously too big before baking, 7.5W felt good before baking and 7W had my toes HARD against the cap and felt too tight.
I still went with the 7W for a roller conversion based on watching @Hills YouTube video (search for TF9 sizing, hockeyreviews) and reading the sizing comments @PBH and others made in the True TF9/TF7 skates thread. I'm glad I did. After baking, I gained a few mm, but they still felt a bit tight. After about 10 hours of use, they felt just right with my toes just brushing. After several months of use now, they still feel very good - snug, but comfortable with good heel lock.
So, if you're a 7.5D Fit 2 in Bauer, I'd say that if you went to a store to try on the TF9 skates, you'd likely think you'd need a 7.5R and the 7R would feel too small. After baking and break in, I believe a 7R is likely the size you need.
If you went into a shop and tried on a 7.5R TF7, you might even think that's too small since the tongue on the TF7 is much thicker than the one on the TF9, but again, I think after baking and break in, you'd want a 7R.
I'm not sure if they tweaked the sizing on the Catalyst skates to line up better with Bauer and CCM. Someone on another forum mentioned trying on a TF7 and the new Cat7 in the same size and felt that the TF7 felt a half size longer (and that was before baking). That's only one person's impression though. There's a lot more feedback on the TF line, with a lot of people needing to go down at least a half size vs. Bauer and CCM.
Customs are another ball game. What I've heard of some people doing is asking for the code from the seller and then emailing True to get sizing information from them.