Installing Anchor Light and Wind Sensors on 19XL

[driversaurus]

I'm installing an Amchor Light and Wind Sensors on my 19XL.

Right now, the only wire in the mast is the one going to the masthead light.

The mast top is a solid cast piece, with the main halyard going through it end-to-end, and everything else pinned on outside of that.

I've figured out how to attach a bracket to this that I can attach everything to, but I don't see an obvious way to get the power and sensor cables into the mast, since the mast head seems solid, and the halyard is in the way of going straight down into the mast.

How is this usually done?  Do I pick a spot below the mast head and drill a hole to pull the wires through? is there anything in there I should worry about?  I figure that a rubber grommet and sealant is the right way to deal with protecting the wire, and to keep from getting water in the mast.

The mast head seems pretty tight on the mast - it doesn't seem to want to jiggle if I take out the screws and yank on it.  Should I try to take it off to see what I'm dealing with?

Same question for the bottom. I haven't looked, but I'm sure there is a hole for the masthead light wire. Do I just add another nearly wire for these new ones?

Thanks!