Sadly BFL stuff is not easily overclockable. I'm averaging about 715Gh/s from 1 minirig SC and 4 Singles(think 12 singles), but they're *HOT* and require 10x the attention the 9 Avalons do. I have two AC units cooling them(32k BTU) and they still overwhelm the ACs during the day.
How did you overclock your singles to 89GH/s per board?
Hi Cablez. If I figure that one out, I'll let you know.

715/12 = 59.58333. They're not only not overclocked they're often slightly below spec, though they seem to love cold and I AM a lifelong Michigander after all. Looking forward to throwing some frosty Michigan winter air at them.
Edit: erk = too fast.