With the thinner barrels, like you have, I have seen a couple of baffle strikes destroy the end of the barrel, so you have to make sure everything in lined up almost perfectly, I also suggest, shooting the particular ammo you intend to use with the suppressor without the suppressor to see how they pattern. That said, as long as everything is aligned correctly, you should not have any problems.
Do you think with the thinner thread pitch that I'll see a lot of POI shift with everything else being equal vs if it was 5/8?
I don't know if others find it true, but my partner and I who also make suppressors, have found that the POI on the thinner barrels has to do with the harmonic vibrations that affect the thinner barrels more than the heavier barrels. I don't know how much POI shift you will see in your situation, but based on what you said about shooting hot loads, I would suspect you will see more with the thinner barrel than you would with a heavier barrel.