Just my 2 pence from this side of the planet. We do not have the products found in the US, so I cannot really comment, but this is the way we do it:
1. Sand the wood down to real smooth finish
2. Apply 7 coats of penetrating marine varnish (thinned for the first 3 coats)
3. Apply 2 coats clear polyester resin (epoxy) by SPRAYING this on.
4. Apply 3 coats of two pack automotive clear coat by spraying it on.
The clear coat protects the resin from UV and the resin gives shock stress protection from bumps etc to the varnish.
We have no ozone layer here so the UV zaps the wood quite badly and this system works!