sorry had a bad night thanks for the response, same architecture as a pi really was hoping some pi users were about
here's a raspi user, currently driving 3 moonlander2 and an old rpi2 for bfgminer off a 'rather pricey' and very powerful USB hub at 796, above they become unstable in a rather unpredictable way. i suspect the usb WLAN dongle i have to use in my setup as a part of the problem - i think i read about USB bus saturation being a possible problem SOMEWHERE, but didn't debug in this direction any further yet...
anyways, the basic setup worked like a breeze. plug your MLDs in, run bfgminer as described in a lot of places, watch your MLDs have fun. however 9 more moonlanders are on their way to me, and i am eager to see if i can drive all i then have reliably with a bunch of hubs and one rpi3, which will eliminate the need of a seperate dongle.
considering that could actually fail, i have a bunch of rpi2 around, and a bananapi routerboard (BPI-R1). i'm kinda sure i'll find a way to make it work reliably, somehow.
shameless self-reply: the 3 ASICs run stable at 900, when i point a fan at them. it's not USB bus saturation, it's temperature. waiting for the rest to arrive today, hopefully.