Wraps, Spine, and Broadheads, Oh My

[Tree Ghost]

I was wondering if anyone had a general rule they apply to their shaft length when they use wraps.  I usually have to add some length to the shaft because the wrap stiffens it.  Does anyone else find this to be the case?  And if so, how much length do you add?  I shoot a 340 black max, out of my 68# schafer with a combined weight of 250 grains (head & insert) up front.

[SlowBowinMO]

I know adding weight to the rear will stiffen a shaft, but I've personally not been able to see any difference with wraps.  That is not very much weight, maybe 10-15 grains at most?  

I do tend to shoot on the stiff side to start with though.

[Tree Ghost]

I was shooting my broadheads the other night, and I'm using the tradgang wraps which are pretty long.  My broadheads were showing stiff compared to my fieldpoints, so I took my zip strip and cut about 4 inches off of the bottom of the wrap and it brought the broadhead arrow back to my fieldpoint point of impact.  I did this with all of the broadhead arrows that I had, they all showed stiff, and when I cut the wrap back they grouped with my fieldpoints.