As you have already seen in the replies to your OP, Unique is an excellent choice for your intended loads (especially since you already have it).
The problem may come when you deplete your current supply by feeding those big cases. Even though many powders are much easier to find now than they were a couple of years ago, it can still be a problem for the popular stuff. And since you have multiple other calibers you like to use that same powder for, best to keep an eye on your stocks and availability. If you have a hard time finding more, or desire to not use up all you have feeding the .44, consider buying some 800-X. It will work excellently in that caliber, and it is generally easily found and cheap (so many people bad-mouth it due to the large flake size that it does not sell out fast).
I personally suspect that most people who like to hate 800-X have never even tried it (or have terrible technique with their powder measures) - they just love to parrot bad things they read. My powder measures throw it consistently +/- 0.1 grain for .357 size loads, but it IS a very large flake, so best suited for larger charges in big cases.