The one thing no one has mentioned yet is that longer arrows fly more forgiving. What I mean is that if form is not perfect(and form is hardly perfect) the shorter arrows tend to follow off the path easier than longer arrows out of the same bow. Spine is very important but setting the most forgiving spine is what I look for in tuning and arrow selection.
When I am setting up a new bow I try several different top manufactures of arrows and even different arrows by the same manufactures to see where the sweet spot is for that bow.
Over the years that has gotten a lot better and easier because the equipment is so well designed now but it still makes good sense.
Coming in from the field and doing some target archery really shows you the accuracy issues with a hunting bow.
All of this is amplified when you screw on a broadhead.
I have shot long heavy arrows well, I have shot short light arrows, and I have shot the arrows somewhere in between. In my experience heavier longer arrows just fly better.
Where I have settled lately for my Z7 is a 425g arrow at 28"'s with a one hundred grain broadhead. The spine charts show that for my setup I am somewhere between the .400 spine and the .340 spine. My bow likes the .400 Easton Axis. That leaves the BH about square with my riser for length.
That is just what this bow happens to like. There may be other combos that work and I suppose you could spend a lot of time and energy looking but...
I have been told that a little heavier spined arrow throws broadheads better, I will leave that up to others to decide.
