The question is:
Is a D97 string somewhere between a FF and a b-50 insofar as it's risk to a non-ff ready bow?
D97 is FF
Use ONLY B50 (or 500) on non FF bows
"Dyneema is a high modulus polyethylene material.[citation needed] It has very similar characteristics to Fastflight, though with a little more stretch. For this reason, many recurve shooters prefer Dyneema and find it more "forgiving" than Fastflight." per Wikepedia
Perhaps the question should have been: where in the range of strings that are No Creep, No Stretch and Low Creep Low Stretch does D97 fall in its comparison to Dacron.
Everything is measured in degrees and I want to know if D97 is less harmful to a Hill bow whose tips are not built up than one of the High Modulus Polyethylene No Creep No Stetch stings like 450 plus. I know Craig (Ekin) said years ago I can shoot FF on the Hill bows he makes with the consequence being a shortened bow life. Would you thing D97 would have less consequenses than 450 plus?
FastFlight hasn't existed for a number of years. Fast Flight Plus is made from 100% Dyneema, just like D97. The difference is in the processing.
Limb tips don't need to be built up for a low-stretch string, BUT they do need to be shaped properly and that's hard to do without an overlay of some kind.
Pad the loops sufficiently and you won't have issues anyway. Don't overbuild the low-stretch strings either (why someone would use 18-20 strands of FF+ escapes me).
Increased arrow speed has it's place. FF on plain tip Hill bows does not. Not so difficult to add FF friendly tip overlays. PM sent.