I tried Xeno 8m HM with my sorc dd in columi gear and it didn't quite work. It was an alt run from my guild and I don't remember how the others were geared, though columi really is not quite enough. I mean, HM does drop T5, so, yeah.
I haven't had an issue yet with people mostly in Columi, but it is my understanding that 8m HM is a bit less loosey goosey than the snorefest that is 16m. Like I said, I haven't bothered with 8m HM yet as I don't see the point.
We three healed 16 HM the other day with all three healers in Columi and a piece or two of BH and I've been in groups where most of the damage dealers were in Columi or WH, as well. We're you augmented?