I am no expert on side drifting but I know what Clancy Holt uses and he catches as many fish as anyone I know.

He uses 8 lb mainline. Very small pencil lead, small hooks, as I remember about size 4s and a 36 inch clear monoleader.

I wouldn't recommend a slinky as you need to change weight to match water conditions.
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No huevos no pollo.