As you can see I traced the shape of the mast head to the angle and did some machining (Hack saw, File and a furrowed brow) to make the pieces look like they belong together.
The red Goo is high temp gasket material for automotive engines I had some left over from a project and I have seen how tenacious it can be compared to silicone. What you cant see is the blue lock-tite that I used on all bolts to prevent their loosening.