I would strongly suggest to get a reloading manual.
I use Berger VLD 168gr with the same powder and I got good results at 64.5gr of powder.
Your mileage may vary.
I think with that bullet weight and powder, max recommended powder charge is at 66gr.
Since you're using heavier bullet, max recommended charge maybe lower -> hence reloading manual is the way to go.
Good Luck!