Yup. Long draws and carbons are a headache… Friend did an extension, sent you a PM… using field point ground to 5* taper…then glued on a wood arrow point to that…gave him another 1″ to play with, but more weight up front! Didn’t need to have inserts in his BH’s though…they glued onto his tapered field point extensions!
As for recommending spine…my, my… seems to me, and I don’t shoot TONS of bows like some do, but in my experience, I’ve shot a dozen different bows, all the same draw weight at my draw length and they all SHOT different…!
Draw force curve, efficiency of the design, lateral and vertical limb stability of the design…all required slightly or vastly different arrows.
My Bigfoot LB came in UNDER my other bows by 2# and I had to go from 400 to 340’s to harness the extra energy Kirk KEEPS in his limbs and imparts to the arrow…where it’s somehow lost in other designs…