Well I finally got my new to me kicker back from the shop 5 months later. So I need a boot for a hole I'm going to drill in the stern to run my cables through. Someone sent me a link for one and I book marked it but I can't find it.
Why not have a glass guy do it? Drill a larger hole than needed, fill 100% with glass and then drill a smaller diameter hole through it. This way no chance of water getting into the core. This is how I'm having my motor well tube drains done. My glass guy says this is the best way.
Another option is to install a plastic sleeve (again larger OD than needed) and epoxy in. Ensure correct material with UV protection.
Do your bookmarks have a 'search' box? Can't tell you what a relief that was when I found that little box. A key word or two, and a few hundred become 2 or 3.