Hi
Would assume you're going to keep it indoors /GH through winter?? A good choice for that type of culture
is a hanging wire basket ose long fibered sphagnum to fill
Plant the SH on the outside through the wire . Makes watering and low humidity much less a problem.. Also you can grow several in a circle as well as another type of plant in the regular way.
If you still want to go the "board" route almost any type of wood will work. Cedar or Redwood is good as it rots MUCH less. Go to the lumber yard buy a piece about the size you want , hanging method of your choice and VIOLA!! cheap mount gary