If you use poplar/birch ply, I'd steer clear of trying to stain it. Neither one of those take stain well without a topcoat sealant of some sort. The stain tends to "splotch" and look like crap once you're done. On the flip side, birch and poplar both take paint very well if you go that route rather than trying to stain it. Either one of those two woods would do well for a rack, especially if you get them as plywood. That would help the dimensional stability so the wood wouldn't expand/contract as much as what a solid board would (end checking and cupping/bowing, etc.). I personally wouldn't go less than 1/2" thick but that's just me. That would give a little more stability and keep the screws from tearing through as badly as they would if you used 1/4". If you're set on staining the wood rather than painting it, you could look for hardwood plywood: oak (red or white), mahogany, etc. Those would take stain better than what would poplar or birch but they're also more expensive and might be harder to find. I know Home Depot carries them but not sure on Mendards. Good luck and please share some photos when you get it built if you go that route.![]()