70grs of FF is a good starting point, I'd prefer FFF as it leaves less residue...
All I shoot are roundballs...I'd start with .490s and go to WalMart and buy a yard of cotton pillow ticking...Then wash it, dry it, cut into 1 1/4 - 1 1/2 strips, lube with SnoSeal and cut the ticking at the muzzle or loading block...
Fresh cotton ticking doesn't burn through as easily as prelubed patches of unknown quality and date of origin...
Anywhere from 70-100grs of FFF is plenty for whitetails in .45-.58 caliber rifles...