Not exactly an answer to your question, as we were in the Sea of Cortez, full-time cruising and had Cetol on our Tayana 37. After a gorgeous professional application, it started peeling in about a month where salt water was constantly splashing on it when sailing or even at anchor.
After a year we were fed up and switched to a product called Semco. It's not "brightwork" like varnish or Cetol, but MUCH easier to maintain (the Tayaya 37 has TONS of exterior teak). It’s reminds me of Thompson's Waterseal, but is designed specifically for teak in a salt water environment. It is not an oil, and won’t turn gummy or attract dirt the way some oils can.
The initial application requires that you remove any existing finish, generally by sanding down to bare wood and then washing with a strong soap. After that, however, there is no sanding and no taping. When water stops beading up on the wood surface, generally after about 6 months in tropical sun and rains, it’s time for a maintenance coat. Application is simple: just wash off the wood surface with fresh water, let it dry and apply the Semco. If your boat is particularly dirty, you may want to wash it with soap first.
No special brushing techniques or expensive brushes are needed – in fact, you can use a foam or bristle brush, a rag or even an old sock. If the Semco drips onto fiberglass, you can just wipe it off with a rag. If you miss a drip and it dries, you can remove it with rubbing alcohol.
Semco-treated teak looks like natural wood, but doesn’t grey or turn black. It comes in several shades and also clear (clear doesn't have as much UV protection, though).
Every six months, it took only about 12 hours of work to put two coats on all of ¿Qué Tal?’s exterior teak, start to finish. Cetol, in comparison, took over a week and still started to peel in less than a month (admittedly we were full time cruising and the teak in question was getting splashed with salt water and drying in tropical sun constantly).
I'll admit that Semco isn't for everyone, but if you're looking to simply protect your teak with a minimum of work (and expense), I recommend it.
Pictures (on page 2 of the PDF on this page)
-- I no longer have the originals to post here, sorry!