protective finish for summer kitchen bench.

I am looking for a protective finish to apply on a summer kitchen bench. I just finished building.
It consists of cypress, ash, some recycled hardwood, red oak plywood and "normal" plywood. It will not be exposed to rain as it is under a roofed surface. There will be a sink and water resistance is needed.
I was thinking of using "Wood Protector" from Osmo. I would like to have a dark finish. Is it possible to add a dark dye to this product?
Is that a good idea. Are there alternatives?

Christophe