I use bark, charcoal and a small amount of perlite. 2 different sizes of bark, medium & small. I like the slashes a bit more than the holes because I don't lose any medium thru the slashes as opposed to the holes which can be a bit messy especially just after potting, after that, things settle in. When I drill holes in pots I get to pick the size of the hole which I can tailor to the mix of medium. I imagine if you want to use some moss-why not? If you have the drainage you can pretty much tailor the mix to what you need for your particular circumstances. More humidity, maybe no moss, less humidity, more direct moisture to the medium, maybe a bit more moss...you pick according to your growing environment. Let us know what you decide to do!