Drill: 4567 Drill
This is another drill that works support hand only shooting as well. I found it at pistol-training.com.
The shooter uses a six inch circle for the target at seven yards. The shooter will run through this exercise four times. For any shot outside the six inch circle, add a second to your time.
1. using both hands to shoot, draw and fire five rounds from concealment
2. using dominant hand only, draw and fire five rounds from concealment
3. using support hand only, from the ready position fire five rounds
4. using both hands to shoot, draw and fire five rounds from concealment.