If you really want advice from been-there-done-that
Friend, I've saved a penny on 223 with small quantities of fast powders and been totally unhappy with the performance. Bullets didn't hit the target as well as I liked. It wasn't worth the savings. I bought better powders (like H335 or Win 748) and stopped wasting bullets down range. The bullets are the most expensive part anyway.
IMR-3031 is a sleeper for 223 Rem. It is surprisingly accurate in 16" barrels, but it meters so poorly in all three of my powder measures that I have to measure each and every round by hand. Once again, no savings over the really good powders. Benchmark is another fast-powder sleeper, but isn't so cheap.
By the way, Win 748 often comes out the winner in load development techniques like Optimal Charge Weight. I find that Winchester powders are still reasonably priced during this difficult time. And ball powders meter sooooo nicely.
If you really want to save money and hit the target with your 55g bullets, find some Ramshot TAC.