Whatever you decide on using, make sure you put the same number of coats on the bottom as the top. Otherwise the boards can cup from side to side. Moisture(humidity) enters the wood the quickest through the end of the boards so seal these real good. One way to do this is to take an old cake pan, buy your wife a new one, and fill it with a 1/4 - 1/2" of finish and stand your boards up with one end sitting in the finish for 12-24 hours and then flip the boards. Don't let the finish run down the face of the wood when you flip them. Spar Varnish is a good choice but high gloss will show scratches more so than semi-gloss. Another choice would be tongue oil. The oil finish is similar to what is used on cutting boards-they're wet all the time. The WARNING ON THIS FINISH is the rags used in wipping it on and off need to be soaked in a bucket of water when you are done. The boards can be spruced up easily while in the truck. Wood Kote 450 would be a good choice as it is high in solids. If you need to touch-up a scratch you will have to lightly (320 grit) sand the whole board before another coat is put on as it will need a mechanical bond.
