When changing the wire from the points to the coil what gauge wire should I use and is there supposed to be a rubber grommet under the points cover where the wire goes through

 

I can't find any grommet shown in the parts diagram. A 1980 FLH should be running electronic ignition stock from the factory. I don't see the wire gauge listed but here's a listing for the points to coil wire …. https://www.jpcycles.com/product/300...-breaker-wires

 

I had very good luck with the Dyna-S in
my Shovelheads

 

That first gen. electronic ignition was junk and known for leaving you stranded. Everyone swapped them out for points back then. The wire size is 16-14 and the blue crimp connections. Either will work.