TC's recommended factory loads for it...
65gr .350 patched RB, 40-60gr of FFFG for approx 1900-2150 MV, 520-670 ME
128gr MaxiBall (lubbed) 40-60gr of FFFG for approx 1760-2000 MV, 890-1150 ME
In actual use 15-60gr Goex FFFG (reduced a little if Swiss), probably a .015" patch for the RB (depending on what the mold throws), and shoot to find what combo's your particular rifle likes for your uses. You can vary patch thickness, but I wouldn't push the powder much higher like I can in my TC Hawken 36. They are capable much farther than the 50 yards commonly printed for them, over twice that in perfect conditions, especially if sighted for a longer PBR.
Have fun, nice find.
.