Yes, I've used it before. 2 Thumb, and 2 thumb lite.
Tried it both ways, gripped same was in your pic and also rotated 90* around so that the big flat part faces the direction of the putter face/target. Seemed to work for a while; took a little while to get used to the weight and gauging longer putts.
Eventually I gave up and went back to conventional grip.. hahaha..