i tried one of those pyramid feeders. it killed 2 out of 5 of my fish, and as far as i could tell, none of them actually ate the tiny amount of "food" embedded in that massive amount of white chalky stuff.
i wouldn't really risk it, IME. wednesday night to sunday is only really 3-4 days, my fish have always been ok not being fed for a few days. but those pyramid things...i dunno.
i just won't ever go near them again, that's for sure.