I have my phals in S/H and they seem to love it, yes I know that growth
medium is just one of many factor ( that I haven't killed an orchid yet
I fully admit is more luck than knowledge, I'll bow to the experts)
BUT for me with haveing to be gone alot I found that having a resevore
in the pot helped alot and that I could vary the moisture of the S/H
medium by mixing hydro corals with Grodan rock wool, for my phals I
have a central wick of grodan up to just below where the roots reach
keeping the mixure a bit more mosit.

and as for flushing / leaching it is easier but you have to watch for
ph and fertilizer concentrations in the container - or just flush it
out every month.

Jack

p.s. I transferred 2 of my phal while in spike over to s/h, and lost
the formed buds, but they put more out since then and are still in
bloom ( I was staying with my cousin who 12 mo old baby and was
fighting a loosing battle with fungas gnat using only insecticidal
soap, and their larval in my bark medium)