Watch the Double Stop Light online guitar lesson by Brad Carlton from Chord Studies: Jazz Turnarounds Vol. 3
Now we're going to take the previous example, but keep a C note up on top. You'll have to hyperextend your ring finger to grab the double-stop in the first voicing, but be sure to keep it upright. In the Ab9, you'll have to hyperextend the fourth finger - rotate the wrist toward the back of the neck to help facilitate this. Maintain the hyperextension through the Gm11, and then you simply move down to get your Gb9#11.