I think your going to need at least 1" of deflection , carbon redline 600's that work on a 40+# longbow = .6" deflection . some of the carbons that they make are numbered by their deflection in inches ,600,500,460, 350 and so on. but I think they may be measured at 28"you might want to check either the manufacturer or one of the other archery forums.
If you can borrow some various spine carbons or some known spine woodies that will give you a data point to verify yours.
I was looking for that spine tester scale print out, so thanks for that.
Roger