If you're looking for full-house loads for 44 mag, it's hard to beat H110/Win 296 or Alliant 2400. I really like the 2400 under lighter bullets in the 44 mag, and switch to 296 for 240gr or heavier. For max loads in 357 mag, the 2400 is super as well (just use a standard primer with this powder, though!). Blue Dot is another good 357 mag powder (again with a standard primer). The auto cartridges prefer a faster powder, and I think you'd find Power Pistol a great match for the 357 Sig and the 9mm.
Having said all that, if you're OK with a little less velocity out of the magnums, but still can get to 1100 fps + on the 240gr out of the 44 mag, then take a look at Unique. I use it in everything from 380 ACP, 9mm, 45 ACP, 38 Spcl, 357 mag, and 44 mag. It bulks up nicely, leaving no possibility of a double charge, and the new stuff burns MUCH cleaner than the old Unique did. It's easy to work with, but doesn't meter as well as some other powders do.
Have fun, and safe shooting,
Brian