I used a 5/8" collet and had a back stop inside the collet. That way I could shove the bolt head in and close the collet with repeatability every time.
Touched off the parting tool at the end of the bolt and set X zero. Backed the carriage out and stepped over .118" for the parting tool and another .190" for the length reduction.
Sad part was I had cut them off with the intention of using the .065" washers that came with them under the bolt heads, but that ended up not working out clearance wise.
I could of used them without cutting them again, but it bothered me, so I just cut another .075" off.