Arrow spine is only a concern when its too weak. However the closer you are to your bows optimum spine, the more forgiving your setup is. Running stiff arrows requires the bow to be better tuned. And your form/grip/release to be spot on. Even cut longer and with the 125 head you are on the stiff side for that bow at 27.5/60. In my opinion youd be much better served with a 400 spine arrow cut at 27.25" measuring from nock groove to end of insert. This will still allow the arrow to be positioned in front of the shelf at full draw.
Does that assume drop away rest, string loop and release?
Not everybody shoots that.
Think one can get too heavy a spine LOL
