You can substitute load data for 300 gr. jacketed bullets, cast bullets of the same weight generally produce lower pressure due to less friction. If you now have a load worked up using jacketed bullets, the cast bullet of the same weight should work fine.
My .454's all like 29 gr. H-110, CCI 450, Starline brass, and the Lee 320 gr. FNGC or Lyman 452651 330 gr.