An added benefit from using the right grip for a left attack is that tori can gain additional kuzushi by lifting up on uke's elbow during the initial rotation. The risk of this counter-attack being successful is elevated if tori's body is too close to uke, thus making it easy for him to grab the leg. This means that tori has not stepped far enough away from uke. The test for correct distance is the attacking leg. If tori's attacking leg is bent when his foot is on uke's knee, then tori is too close.
Optimal distance is when tori's outstretched leg is straight when the foot is on uke's knee.
Tori has launched his kuzushi. Typically, uke will want to take a step forwards with the right foot in order to regain his balance. But tori blocks the foot and leg movement by placing the sole of his left foot just above uke's right knee. Throughout this early phase of the throw, tori should be leaning slightly back to the left in the direction of the kuzushi and turning his head and shoulders, aiming for a 180 degree turn, in the direction of the throw. If uke's leg is successfully blocked at the knee by tori's foot, and if tori has successfully applied the kuzushi so that uke is seriously off balance to the front, uke should 'pop-over' in a tight, almost horizontal spinning motion onto his back.