We tried Owner Assists on the rear of some poppers (tan cord, pink hook), mainly Skipjacks. I lost interest after a "tuna" leaped clear of the water and engulfed my Skipjack. Although it was during a Mac Tuna frenzy it was obviously not a tuna, rather a very large Spaniard, my assist was sliced in half in half a second flat, I hardly felt any pressure (at the time, and still currently a Spaniard is high on my "TOO CATCH" list...yet I missed it). The point i'm trying to make is that using mylar, kevlar or ziotspecialsuperstrongcordelar a toothy critter will ablitterate you, no matter what. Yet unlike a wire trace on a trolled lure, or floated pillie, a wire assist will have no negative effect on your target species if using as a wire assist on a rapidly retrieved lure (ie popper).
Double strand/overhand etc = why bother. Use wire assists if popping for GT's/ They catch the unexpected toothy critters (which generally are regarded as genuine fun captures anyway - Wahoo, Spaniards etc). The only exception is sharks...and when was the last shark on popper capture recoreded...no doubt Brandon has a story
but the fact is it's that it'd so uncommon it's not worth worrying about.
Screw the assist cord, zero benefits, bulk losses. Use wire or splits and swivels. Just my 2 cents.