Im replacing the wiring from my boat (the old glasspar I've referenced
for those who might remember) and I'm wondering what gage wire I should
use for it? Mostly it's for a horn relay set up (3 buttons) and the
main pos and negative wires. I figure it's close to 50 years old, so I
might want to replace it.

Thankfully, there isn't much wiring TO do, outside of the horn lines
and the main power lines (actually, outside of the main wiring harness
(which I'm not touching) there isn't any other wires other than the
main battery lines which I already have wires to replace).

I'm also trying to figure out how to use the least amount of wire for
the 3 horn buttons (I can almost mentally picture how to set it up, but
I keep running into blocks). You guys have any advice that I can use?

Thanks