I have owned and shot all the Centaur models and several Thunderchildren and Buffaloes.
A fully loaded bow from either bowyer would be hard to choose between, both are top shelf with customer service to match.
The Buffaloes IMHO shine at the longer lengths 64 and up, because his limb design is wider and flatter with a less radical taper from fade to tip, this is magnified in the shorter ones 62" or less.
Centaurs have a short riser fade to fade with a narrow deeper cored limb that tapers to a very narrow tip, with a long working section. Pound for pound definitely more springy feeling with a very even smoothness almost an even 2.5#/inch all the way to the max. The Buff feels more like a classic r/d longbow, but again like I said they are super smooth to me in 64" and up. If you genuinely want a shorter Big Jim bow I would rather go with a 58" Thunderchild.
Big Jim now offers G10 risers with scales also, and can cut them past center, so the sky's the limit on how radical you want to go. I have seen some of the latest work with his resin impregnated burl woods and it's insane.
Jim Neaves can do the bows without finger grooves too FYI
Both bows from either maker are whisper quiet when tuned.
The glass Centaur is quicker.
Both are very forgiving. The XTL lam will add torsional stability and durability.
If you want a bow that has the feel of a hotrod sports car taken to the limit, a bow made into functional art, the Centaur is a natural choice. They are special, and I'll be honest they shoot so well for me I keep selling them because it takes the challenge out of it! LOL
If you want a bow that showcases elegance, artistry with natural materials, with the spirit of bowhunting deeply infused into it and a real signature to it with great performance than a Big Jim bow is a natural choice.
My advice would be to keep looking at pics, talk to both bowyers who are extremely approachable and friendly, and if possible shoot one of them similar to your specs, and then decide.
Best advice, get one of each!