My experience with throats in .44s made by S&W has been that it is often the case they often have a slight constriction for the fist handfull of thousandths from the front of the cylinder and the rest of the throat is larger. A reamer fed gently from the back scrapes off this upset metal very easily and uniforms the throat.
If you insert a pin gauge from behind, you might find it fits into the throat but won't *quite* pass the front edge of the cylinder and then you know.
Sadly, my experience is usually that they run large rather than small, so consider yourself very lucky!
It's really best to slug your bore before making any decisions, but assuming that's fine I would find a bullet that I liked for price and profile and start reaming those throats in .0002" increments and shooting groups until magic happened or at least until the bullets were a firm push out from behind.
I believe the factory used a gang-drill/reamer, so by using the same reamer in all chambers you would get a more uniform cylinder out of the deal.
Norma JHPs are sized to .429 FWIW.