45 Caliber Knight ultra lite

I recently obtained a Knight ultra lite in 45 caliber with the one in 20 twist. I have some 385 grain no excuses bullets sized .451 and also some keith 250 grain bullets sized to .451 , any suggestions on charge weight for these two bullets using 3f triple seven? Gun shoots great with 195 grain knight sabots and 77 grains by weight of triple seven 3f but I prefer a full bore conical.
Thanks in advance.

Triple Seven is HOT Powder, I would try 70 to 75 Volume (60 to 65 by Weight) with the 385 Grain. I would try 50 to 55 Volume (40 to 45 Weight) with the 250 Grain Bullet

I get best accuracy with Cast Lead bullets at 1,300 to 1,450 FPS, Much over 1,450 FPS and accuracy starts to suffer