I guess it depends on what you want at 300 yards. 2-3 MOA should be possible without too much headache. We wait for calm days before trying as the wind works on lower velocity cast loads quite a bit. Somebody to spot hits really helps work out elevation.
See if you can find some Alliant 2400 locally, it would be my first choice. Alliant Unique or Herco might be my second choice. Alliant powders seemed to be the slowest to come back in stock. Maybe someone can suggest some Hodgdon powers?