Good question...just have to sneak up on it. Takes just a bit of practice but not much. All I ride are 2 bolt posts and so I know precisely what you are talking about. Find a saddle tilt you prefer which btw takes me a week of riding...because I am fussy about weight distribution on the bike and clearance for important parts in the drops.
Once you figure this out...gradually increase torque on each side...a few in-lbs on a side..increasing torque a little at a time first bolt, then the second. Important point is, not to overtorque a two bolt post. No need. The beauty of the design is saddle tilt will stay nicely in place even with low torque. What matters however to maintain your saddle tilt is precisely the question you asked. Equal bolt torque is what matters the most...and not exceeding 55 in-lbs for each bolt would be my suggestion. 2 bolt seatposts are the best.