In the original warranty, and in his book (I have a copy), Harrison had a bit to say about the superiority of endless vs. flemish. He not only voided the warranty if you used flemish, he voided it if you used polyester ("dacron").
To put it mildly, I disagree with what he said. That stuff was plain off the wall.
Properly made, there's little difference in performance, if any. Endless is usually noisier, especially on a recurve, but either one will do the job just fine.
Never saw a string twist a limb either. Heard that claim made about a 72# longbow once, but it was pure bunk (I held and shot the bow).
I have seen folks shooting strings that had so much twist they coiled up when the bow was unstrung. I suppose if the draw weight was light enough and/or the limbs...well, the only word I can think of is flimsy...flimsy enough, and the string was twisted way beyond what a normal shooter would use, maybe it could.
You can twist an endless just like you can twist a flemish though--in either case, that would be putting the wrong length string on a bow--can't blame the string for user error.
Chad