We just had delivered 400sq ft of mahogany porch flooring (tongue/groove) and my hubby is totally confussed!

1. Paint or stain--which is better?

2. IF stain (we are favoring that) do we leave the bottom un-stained (to let it breathe?) and DO WE COVER the tongue/groove side?

3. WILL it turn black from sunlight if we stain/waterproof it? It's mostly in the shade of two huge pine trees.

What would you do to ready it for laying down on the porch and what about what type of fasteners (anything special?).