I always spin my broadheads first and tune the arrows in. I spin the arrows with the BHs installed over an index card. I look for point wobble. If it wobbles, slow down the spin, and see which way it is pointing. This is how it will fly out of the bow. I heat up all BHs on the shaft carefully then rotate the inserts one rev or so and stop when the blade lines up with the fletching. Supposedly, it doesn't matter, but ti does to me. It's one of my head things. By rotating the insert in the shaft you can reseat the insert to be inline with the shaft. You have to mess with it. It works.

As for tuning, my norm with fixed points is that they shoot low, left of my field points. 2" LL @20 yds, 3" @ 30 and 4" @ 40 yds. They are grouping great so I adjust my sight for the BHs. I have 3 bows that only shoot BHs. So changing sights isn't a problem for me. I have a target bow also.

You can tinker and tinker and get BHs and FPs to have the same or close to same POI. But I believe that the difference in point length between FPs and BHs changes their FOC slightly. Sometimes enough so they will not have the same POI.