If you can take a Big 3 1.5" 3-Blade BH and place it virtually touching a fletched arrow w/field point from 5 to 25 yards, your are hardly underspined nor overspined.
My personal set-up does just that.
51 @ 28 (1/8" past center)
Victory HV 350...29.5"(6.7 gpi)...100g insert...300 gn head...615 g total...32% Ultra-EFOC
"Bow's required dynamic spine is 70# where my actual arrow is 40#s".
When shooting these arrows, virtually all I see is the nock. Please attempt to reserve comments concerning the flight characteristics and performance of Ultra-EFOC arrows until you have fully experienced them for yourselves. If the set-up proves all hype for you, then just scrap it and you will know first hand. Note: These types of set-ups were difficult and cumbersome to develop in the past. Not now!
Don't miss out on a great possible enhancement which you can easily discern the advantage. This set-up completely disentegrated a 1 yr guarenteed 18 in 1 Rhinehart in less than a month.
The results should not have even been expected from an extremely high powered set-up. My results for this particualr set-up proved not to be all hype and just on paper.
Also, try to acknowledge ,as drewsbow noted, that a particular set-up may work for one and not another.