You take the wires out of the plug then send them through you dont have to drill out the hole fro the plug to go through

 

I've never, in all the years I've been involved with H-D liked those flat light bars. First thing I did when I bought a low mile 2001 RKC last fall was ditch that thing for a far more compact bullet light unit with LEDs. No fitment problems whatsoever.
I do LEDs on every bike. Run/brake/turn modules for the rear also. Because like the OP, I like to be seen. We may have taken different methods, but that doesn't mean one guy is right and the other is wrong. The comments from that other person about the OP's riding experience are bullshit.

http://www.jpcycles.com/product/320-345
http://www.jpcycles.com/product/446-561