Devcon
Devcon 2 ton epoxy dries clear and hard. just make sure to mix really good.
I have tried Loctite gel and 401 for ferrules and I'm not a fan...
Gorilla glue does not dry clear, so that might be an issue, I have bought some west system G/flex, but I have not tried it yet.
Devcon 2 ton epoxy dries clear and hard. just make sure to mix really good.