Fritz, TC's manual lists 70-100grns FFg for the maxi's in the 240-255grn range.
I personally use 90grns Goex FFg, an oxyoke wonderwad, and a 255grn maxi-hunter in a standard 1:48" .45cal flintlock I have...tack driver...took another deer with it just week before last.

Suggest you clean the barrel to the bare, raw metal, then keep it clean using strong tight fitting brushes every time you clean it...buildup from lead bullets can affect accuracy...the prelubed oxyoke wonderwads work as an outstanding firewall between the flames and base of the lead maxi's to minimize this.

If you do try the wonderwads, I suggest you get the next larger size caliber wad...ie: use 50cal wads in a .45cal, etc...so under the heat & pressure of ignition, they compress all the way out into the grooves and really tighten up the seal between the fire and the projectile...increased velocity, improved consistency, tighter groups, etc