Awesome. I honestly only know a few growers who've been successful with armeniacum and micranthum (in this area). I'm always envious. I LOVE the yellows and of course, armeniacum is the ultimate yellow paph.
Yes mostly pumice and 10% small size coconut husk chunks (for organic material) in clay pot with holes. Previously I had them in fine mix in plastic pot, and usually that will kill all the roots.