In My Humble Opinion,
Kindrag, I'd say that since most ppl like this mix, then it sounds just fine!
most of it is finding out what works in
your environment. I would say, to simplify things/give y'all a good baseline, to have your phal dry out (& need re-watering) within 4-5 days, is good, that is what you want, and should pretty much aim for that. ...but all of this also depends on your conditions, & how much time you have to water ~ for example ~ some ppl who use spag, (wouldn't suggest for a newbie, but just wanna show an example), ppl who grow in greenhouses, with little time to water every single plant (like some phal growers, that don't water overhead) they water every few
weeks, not every few days. However, that said, for y'all, I would suggest aim for needing to water every 4-5 days.
Also, you can always modify this mix, if it's not to your liking, if it stays too wet, you could take out the chunks of peat moss, and/or add more horticultural charcoal, LECA, or Lava rock, etc. ~
OR ~ if it stays too dry, you could add in a little chopped up spag into the mix...etc. I will say, that this mix (going by the ingredients, I haven't seen/used this mix first-hand), does sound good for Phals (hell, w/o the peat moss, you could use it on Catts, Dendros, etc.) Growing orchids is more of an art, instead of a science (where everything, everywhere is concrete... Growing orchids, ya just gotta figure out what works & what doesn't in
your environment.)
Optimist, if your roots are staying moist, and happy inside those 4 days, then
leave them the way they are .... But, if they need more moisture (since ur in a dry climate), you could try adding/modifying your mix w/ chunky peat moss, Or adding a little spag
to the mix (wouldn't suggest for a newbie to use either of those ingredients by themselves... Like maybe 60-75% of your mix being this store bought mix, w/ the rest/balance being spag moss). ~ Or ~ you could just put a small layer of spag moss on top of the mix.