I took all the boards out and laid them out in my garage at home.
I sanded down with a random orbital 150 grit. The teak veneer is thin but I never had an issue going through. In order to get a good finish you need to remove all the old stuff and get back to bare wood.
I then applied about 4-5 coats of epiphanes (sp) marine satin finish varnish and they looked like new. It is also a very durable finish much like a hardwood floor finish.
Make sure you vaccuum /clean all the dust and try to let the air settle before you apply the final coat. I did sand lightly between coats to get a better adhesion and cleaned and dusted.
I tried to fill some of the dings with filler but that was a waste of time as the color match was off and they looked more obvious.
The swiffer dusting cloths are good for the final wipe.
It was a winter job.
Good luck