Rolex Authorized service only! Yes you will pay more, but here is the thing, if you go the cheaper route with your independent guy, and there is some thing he can not fix or screws up and it needs to go to Rolex, they will hammer you on price. My watchmaker who has been teaching me, is a Authorized Rolex service tech and sees it all the time. Unfortunately for him, he has to bare the bad news to the owners that the cheap alternative that serviced their piece last, did more harm then good. Instead of a $550 they spend much much more, plus what they paid the cheaper service guy.
There are plenty of qualified people out there like Z that are more then capable of doing the work however, there are even more that are not capable. For a piece of mind and potentially more money in your pocket, get it into the right hands.
Talk to your local or out of state AD's, some have in-house Rolex Trained Service techs that can do the work their in the store in a week and will not have to send it to Rolex.
Like above, I only send my Gen