Your options are The Patched Round Ball and such conicals as the Maxi ball the maxi hunter and Power Belts some 1-48 twists shoot saboted bullets fairly well for that twist I would suggest the shorter bullets such as the 200grain 45 in a 45/54 sabot or the 300 grain 50 caliber in the purple 50 /54 sabot.This worked well for me in a 1-48 twist TC Hawken.
Actually the Patched round ball with about 90 gr RS usually works well though you may have to go up or down a bit for the best results.
Most 54 take a .530 or a .535 ball and a ticking patch lubricated with olive oil or Bore Butter.
Do take time to sight it in I suggest sighting it in at 1to 2 inches high at 50 yds for normal deer hunting unless you will be hunting open spaces then you will need to find just the right combination of things and sight it in much farther out.