It occurred to me to toss one more insight into what I've learned with the King Kandy cut plugs, actually coming from the rigging on their needlefish lures.
The cut plug and full sized herring come with a few strips of foam that go into the rigging for holding scent. All's well and good (and the scent does seem to help), but the foam strip is gone with each fish. I was searching for more to cut my own, when another thought occurred. Their needelfish are too small for the foam, so they tie in a strip of yarn. Bingo! Once the foam is gone I've been tying yarn into the rigging of the cut plug. Probably won't even mess with the foam on new ones, because the yarn stays put even after you catch a fish.
A bit more on rigging. They come rigged with what looks like 30# mono. It's been fine so far, but I'm more of a 60# leader kinda guy. I also prefer different hooks to theirs, though I haven't lost a fish yet on theirs.
I'm rerigging with the same length of 60# leader and swapping to 7/0 Owner Cutting point hooks for the lead, 5/0 of the same model for the trailer. I'm a sincere fan of those hooks, so it increases my comfort level to have them there, necessary or not.