As for the question of wear on the whoopies, I've wondered that myself. Not so much with `biners since their edges are round, but more when using DutchWare / Elephant Trunks / etc. since those pcs are square-cut and the Amsteel or whatever you're using has to bend over those edges.
I have no experience with these items since I've only used quick-links and MSH setups on my rigs, so maybe someone with a lot more hang time can jump in here . . .