Give Hogdon a call, they may tell you the formula which they told me,  mark the case where the bullet would seat when in the case, mark, load case with tb to the mark ,dump weigh, then start with 75 percent of this to start.  This is from memory so If I were yor call em..
I have tried TB, but now use Unique for light loads even for 500 yd  plinking, got my info from old Lyman books like number 40 to number 45 books, if you would like my loads, email me... I have them for 32-40, 38-55, 40-65, and 45-70..and I do not use any fillers or wads keeps fron rings in the chamber.. Good luck..