Do NOT use Silicone. Silicon is a piece of shit product and if you use it the lights WILL leak. I would never silicone anything, except a water pump gasket, on a car I cared about. I would get some plastic/rubber grommets from “Hectors Hardware”, run the wire through those and then COMPLETELY seal over the top of the grommets, roof panel, and wire with “JBWeld” epoxy , “3M Automix Seam Sealer”, or “3M Automix Panel Bond”.