I have installed several beadboard backsplashes. Conversion Varnish is the way to go to make them last. So far all were done over a short quartz splash, which gets them up a few inches from any potential spills. You can usually get a counter top fabricator to add the "curb" splash for very little extra, since there is excess material from the slabs. Make sure to back-prime, and prime the butt-ends.