I would take the IWC to the NYC Boutique (i have had three done in the last year).
My 3714 had not been serviced in 8 years. Major overhaul, case polish and new Strap ran me $900.
It is painless, as they take care of all of the Insurance, Fedex etc. to Richemont in Fort Worth. Quickest turn around was 6 weeks.
I would not trust them to anyone else, (as with re-crafting of my EG's to the UK)....Just my 2 cents worth.