Regardless of whether you are loading with Unique or other powders, use what primers you have or what you can find. Your gun, your components, and your shooting skill are different from those of others.

I've seen slightly better accuracy with a magnum primer, #2400 powder, and a 160 gr. SWC cast from an H&G #51 mould and fired in a 6" Python vs. the same with a standard primer. Hardly definitive proof of anything.

Try both primers (or as many varieties as you can find) and fire some ten-shot groups benchrested at 25 yards. A chronograph would be handy, but not necessary. If you use a chronograph, look at the velocity figures and check the target for group size; don't fixate on SD and ES numbers which are very secondary.