I know the authors pretty well...
Some caution should be used, the article is fairly old. A few of the growers who were using the mud mixes are not doing so any longer. EFG springs to mind, they switched back to bark, more for customer acceptance than cultural reasons. Also, most people using mud mixes now are using either all coco-peat or a substantial portion of coco-peat in place of the sphagnum peat.
Going from memory, but I think Hilltop is using Scotts Metromix 360 (380?) with coir, plus some seedling bark, plus some perlite and charcoal. I can't bring myself to add bark to mud mix, so I leave out the bark, add a bunch more perlite, and lately a good bit of an expanded aggregate called Haydite. I've considered adding some small diatomite, but haven't done it yet.
My 'grower' (friend who helps me out for free and probably knows more about orchids than I do...) has switched us back to a bark mix for the phals as of this summer. I'm still not convinced. However, in my conditions over the winter, the top growth was amazing but the root growth was not as impressive. I say screw the root growth, since it is obviously sufficient. But, I wasn't doing the repotting. Plus the pots tended to tip over with tall and heavy phal spikes, especially just before watering time. I'm still using mud on epidendrums and some other things.