The plated jacket is softer than a standard jacket and won't require as much powder to reach the velocity. Most plated bullet producers also admit that their larger diameter bullets (.44-.45) should be kept below 900-1000 fps.

How much less powder is going to be dependent upon bullet & powder in use. I can tell you that with 9mm 115 gr bullets and Unique, I can drop the charge 0.4gr and keep the same velocity going from a standard bullet to plated. [Keeping the same charge gets me an extra 100 fps and leading issues. Depending where you are in your load data, you may be able to just drop a plated bullet in without changing the powder charge.] That's probably a reasonable increment to try-so long as you don't go below established minimum charges as shown in loading manuals/powder manufacturers websites.

I didn't change any of my die adjustments and haven't had issues in a couple of thousand rounds.