Inexpensive test
Get the Starbrite three part cleaning, brightening, oil kit from West Marine or Boat U.S. I'm not promoting this brand per se, but it is an inexpensive way to test how well your teak restores.Treat all the teak as if it were incredibly dirty, and follow the instructions on the bottles. After scrubbing with the cleaner, then allowing the brightener to work (maybe a few minutes longer than they suggest), you'll have an idea of restoration color before you apply the oil.At least, you'll have a benchmark.