How do YOU fire form Ackley Cartridges?

Unfortunately factory ammo is next to impossible here to find or is STUPID in price. I have 100 brass and can get lots more brass.

I was trying to find some H1000 to reload up and shoot but this H50 was cheap.
One of the gentlemen here does a lot of 257 AI and he was suggesting H1000 and a few other very slow burning powders behind a fairly heavy bullet. He mentioned that when he went with slightly faster powders that he didn't get as good of fireformed cases.

My trouble is... with the scarcity of powder, I kind of jumped at 2 lbs of H50BMG when it went fairly cheap. So I am kind of second guessing my decision a bit here.