Brent if you check the Alliant and Hodgdon website you can find 1 1/4 oz loads that are really close to the RST load with 572,Longshot, Blue Dot and Herco . Unique is also good but not quite as low. Federal Gold Medal hulls and Cheddite style hulls are the way to go. Lots of wad and primer choices.
I use Blue Dot and Longshot but I don't think my loads go quite that low. Part of my problem is using WinAA hulls and wads. Straight wall hulls seem to average a bit lower pressure in comparable loads.
The RST loads were looking almost like SRn7625, which I really like but is no longe made. I have about 2-3# left however.