https://www.fenderarchery.com/blogs/archery-info/basic-tuningRead the entire tuning link above then do your broadheads.
Fine Tuning Broadheads
For the hunter, this is the bottom line, broadheads that fly true and straight where you look every time! It would be nice to think that with all the tuning you have done to this point that you could just glue on matching weight broadheads and get perfect arrow flight, that rarely happens but you should be close! The blades of a broadhead try to plane and steer the arrow so any small tuning problems that were not detected prior will be magnified greatly. I can't emphasize enough how important it is to shoot your broadheads and correct any flight problems BEFORE YOU GO HUNTING WITH THEM! After tuning and practicing with your broadheads, be sure to re-sharpen them to a razor edge.
If a person is so inclined, you do not have to tune your arrows with bare shafts and field points. A person can go straight to broadhead tuning. Bare shaft tuning using the planing method is useful to either get close to the correct broadhead weight, so you don't have to buy a bunch of broadheads, or if you are only going to target shoot with target or field points and never shoot broadheads. This broadhead tuning method and the bare shaft planing method are exactly the same thing for the same reasons.
For tuning purposes, we should use the biggest/widest/nastiest broadheads possible. If you try to do your tuning with very narrow broadheads you will not be tuned as well as you could be. Once you are tuned up with wide broadheads you can change over to narrower heads of the same weight with no problems. However if you tune up with narrow heads then try to switch over to wider heads, you'll find you weren’t as well tuned as you thought you were. I prefer to use Snuffers for tuning, then I can go to any matched weight narrower head I desire depending on the game I'm after.
The first step in tuning your broadheads is installing the broadheads. Straightness is a must, spin them on a flat table or in a cresting jig to check for wobble. You can spin them on the tip but the very tip can be filed slightly off center showing a wobble that won't cause a flight problem or vice versa. A person should strive to have enough stabilization without having too much. 3- 5" fletching is way more than enough for the biggest broadheads. If you are going to shoot very narrow broadheads, 4" or even 3" is plenty depending on your center of balance. More fletching makes the arrow stabilize quicker if the arrow is disturbed but at the expense of rapid energy loss and less bow clearance when we screw up a release
In theory, the orientation of the blades to the fletching or your sight window should make no difference but, I feel they should at least all be the same from arrow to arrow. I mount 2 bladed heads horizontal and 3 bladed heads "V" up. I do this for two reasons, most folks mess up a release more often than any other mistake. This results in more side to side "kick" than normal and 2 bladed heads mounted horizontal will not plane as badly, arrow rotation due to helical fletching starts slowly so the arrow is flying for several feet before full rotation starts. The other reason I mount my heads this way is I don't like anything sticking up into my sight picture that isn't there normally when I'm practicing with field tips.
Remember the arrows must be identical in every way other than the points. Our goal here is to get your broadheads and field tips grouping together from as far away as you dare to shoot. That is the tuning test. If you can stack wide broadheads, bare shafts, and field tips in the same group from as far away as you can shoot a group, you are well tuned. If you can't, you have tuning problems period.
Get back 20 or so yards from a suitable broadhead target and start shooting field tips and broadheads at random at a spot. Take a look at the diagram below: