The real reason most builders don't stain wood is simply because you're taking a gamble with epoxy adhesion. With all tht work at stake, believe me, it is a gamble. Most builders over the years are going to less fine sanding to get a better epoxy penitration into the fibers during the glasing stage. Put the effort into getting darker wood for you contrasts - it will be worth it. Sometimes I find chocolate brown dark cedar at Home Depot. Garbadge wood but I get some nice dark strips out of it. If you do stain, don't use oil base. Even some of the water based stains have acrylic which seals pores. Try to get the alachol stains. You'll probably have to go tho a woodworking supply house for that or make your own using artist watercolors and alachol.