Sit in the water as you did for Drill #3. At every height in the water (alligator low to showing stomach) move directly forward, backward, left and right. Then test every angle in between.
Moving forward quickly may require your leg positioning to be more vertical, while moving backward may require your leg positioning to be more horizontal. Test it. Moving left and right requires coordinated movements in your legs and feet so that the lead leg is pulling, while the back leg is pushing the water past your body.
Each body is different, which body and leg positions are most efficient for you in each movement?