Welcome, AmmoNerd!
I think 40 S&W is an excellent cartridge in spite of the fact that when it came out I was almost certain it would soon be a mere footnote in firearms history.
I've owned a couple, reloaded for them, even shot them a fair bit. Someday I'll have another.
At the same time I have to add that Sevens is spot-on, as usual. But since you've been lurking here for some time, you should already know that, AmmoNerd. Your attention to detail will serve you well loading for the 40 S&W as it has little margin for error and the results of even the slightest carelessness can be quite dramatic.
As noted above Unique has a loyal following but other powders are simply better suited for the task at hand, Universal Clays will do anything Unique will do, cleaner and better.
I don't think anyone here wants to tell you how to do things, just trying to let you benefit from their often considerable experience. Ultimately the choice is all yours, please be careful, my friend.