When I started loading about 35 years ago, Unique and Bullseye were just about the only powders that I used, but then I only loaded .38 and .357 magnum. I no longer use either one of those powders, so the loads I show above are directly out of the manual. I use mostly Accurate #7 in the .357.
Unique is a great powder for mid-range loads and every pistol loader should have some on the shelf. The new stuff is made with better cellulose so is much cleaner too. It's very forgiving, and is bulky enough to (usually) avoid any double charge mistakes.
You could use either but no need for a magnum primer here, just use a regular small pistol.
I recently did some testing to see if there was any difference all other things being equal between magnum/standard small pistol (.40)
the velocity was pretty much identical but the ones with mag primers showed more flattening. Not sure if that's a pressure indicator or just a composition of the primer difference, but with magnum primers, stay on the low end of the charge weight initially.
I believe magnum primers provide better/more consistent results in extreme cold weather?