Nice! I settled for grilled Wahoo! I had YT for lunch. I still have a tonnage to go from my freezer.
I have noticed line twist using the keeper.The sliding sinker rig with swivel above the leader prevents the line from becoming twisted up. A free floating leader tends twist with the current (the weight will roll on the bottom), the ebbs and flows will also cause twisting.
The same thing can happen with a surf leader rig. In that case I’ve learned use a snap swivel at the weight end, and one above the leader. As for fish twisting the line up, I've never really noticed that, mostly stretching nearest swivel. The snap and swivel are also good for quick change leader (fresh bait).
And its difficult to use a sliding sinker witiout a swivel as a stop, even the barrel sleeve setup uses a swivel (sturgeon rig). I'd suggest a red bead, above the hook's eye.
I think the lead sliding is intentional, not sure how it impacts effectiveness, but the lead sliding allows the line to be pulled by the fish without getting spooked by detecting the weight. Carolina Rig is same concept as the fish finder rig with less hardware.Use 2 keepers, 1 below and 1 on top of your lead.
It's the lead that is sliding and pounding into your keeper that makes it slide down.