A: With painting and/or sealing all six sides is always ideal
yes -- I would! (exclamation point) I might even recommend a stain and sealer in one (miniwax first that comes to the top of the head) as a time saver, but may, if time warrants, even consider an additional clear coat (but make sure it will adhere to initial finish). For a job like this -- I would suggest stopping into a local paint speciality store to see what they have.
That said -- beadboard and other paneling is notorious for expansion and contraction even with taking these measures. If you have control over material selection - I would suggest choosing the stock wisely -- preminium boards if you select pine, with a low moisture content. The whole project too may benefit with some acclimatization time. i.e. A chance to be stored in the room where it will live -- maybe up 72 hours before beginning the project.
Hope this helps. jb
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