I just installed one on my 05 (right dash panel)
I had the benefit of having all of the plastic off the bike (& I mean everything)
I just bought the bike (new to me) w/9500 miles on it and wanted to do a deep cleaning. I was also putting on a set of frame sliders, fork brace, fenda extender, radiator guard and horns.
My .02 is to test fit, route the wires and make sure it all fits under the plastic. Measure twice (or more) drill once. I had the powerlet plug routed up behind the battery where I though it would work. I put a rolled up piece of tape on the top of the plug and dusted the tape with a little bit of baby powder to transfer a mark to the dash panel. Then I drilled the hole and finished the assembly. Might be a bit of overkill but I did not want to ruin a panel with a hole in the wrong place.
I picked up an 11/16" drill bit at Lowe's for $1.99, worked like a champ.
I preferred that to using a dremel to enlarge a more standard sized 5/8"
Maybe you could borrow a drill from the seller, and just bring your own drill bit?
Good luck & enjoy the ride home!