Teak or Rosewood bathroom vanity top
 

I am concerned with what to use for a water impervious finish of a teak
wooden top for a bathroom vanity. A paint specialist suggested a
marine varnish. Another suggestion is to go with polyurethane. Yet
another is to try leaving it unfinished applying teak oil as needed.
Also, I am aware of using automotive clear coat as an ultimate finish
protector.
If the wood is not teak but is rosewood instead, would the
recommendations change?
Any suggestions?
Also, we are concerned about the wood appearnce after stripping and
sanding. It had been stained before and in some areas the stain is
obviously soaked into the wood more. What should we do about this?