In case anyone is still running old iron here is my config for my AMD HD 6970s.  If anyone can improve this,,, please feel free to make suggestions.

On GPU0 @ I 13 I am getting 617 Kh   ( run this GPU at 13 while using the PC)
On GPU1 @ I 18 I am getting 1.679 Mh

"intensity" : "13,18",
"worksize" : "256",
"kernel" : "x11mod",
"lookup-gap" : "2",
"thread-concurrency" : "8192",
"gpu-threads" : "2",
"gpu-engine" : "880-880",
"gpu-fan" : "30-55",
"gpu-memclock" : "1375-1375",
"gpu-powertune" : "20",
"temp-cutoff" : "90",
"temp-overheat" : "81",
"temp-target" : "75",
"api-mcast-port" : "4028",
"api-port" : "4028",
"expiry" : "28",
"failover-switch-delay" : "60",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"log" : "5",
"no-pool-disable" : true,
"queue" : "1",
"scan-time" : "1",
"tcp-keepalive" : "30",
"temp-hysteresis" : "3",
"shares" : "0",
"kernel-path" : "/usr/local/bin"

This is my first experience with the X11 client.