Not many provide this service
Not sure about the "plenty of guys who can do it" comment. There certainly are a few who have done it themselves. There are even fewer that do it for others. In fact, I have only seen three. I would only recommend one, Bil. He has the history and the track record to back his retros up. When you are willing to spend this kind of money for headlights, you do not want issues. Go with the best. I have no affiliation with Bil or his business.
BTW - I am not speaking about my experience from what I read in the threads here, even though that is a very good indication of quality work. I am speaking from direct experience from three different sources I have dealt with.