before jumping through a bunch of hoops, i would try bigal51's suggestion to clean the inside of the headlight assembly. plenty of videos on youtube show how. then make sure it is aimed properly after you reinstall. a good clean lens, aimed properly, can make all the difference.

 

I believe the bike came stock with sealed beam LED’s. Btw they all get condensation in them from heating and cooling. The amount is dependent on the climate .

 

So, the stock lights are sealed LEDs. For cars, I sand the outside and spray two coats of clear. The HD LED lights lens is plastic, the old school is glass. I didn't like them from the first ride due the flat line of light and everything dark above it.. Even added two extra flood lights for running on the backroads.
I now have the old school lights installed. Still waiting on on the 100w H9 bulb for the high beam. Using the 65w worked but I want to be able to blind A-holes that can't turn off their bights. It is a big problem around here and it seam like its the Uber drivers.

When I get the 100w installed I'll grab some photos and post. Wiring was not a big problem. The 15 has a four wire plug, Ground, Low, High, and small lights. The last is used to wire lights on the outside of the bat wing.

 

The wiring on the Rushmores is much smaller gauge than the older bikes. I would seriously consider not attacheing a 100W incandesent bulb to that. Your bike - you do you.

The early Rushmore Daymaker bulbs aren't sealed, there are paper stickers over some holes in the heat sink / back of the bulb. The white film is common in the lenses and you can take them apart - I did the main bulb and both spots on mine. The black glue holding the lenses on releases with the gentle and constant pressure of a flat blade screwdriver prying them off and a SMALL amount of black RTV works fine to reseal them.