The 1st attempt to eat while driving had the center "angle" at a 5. This tends to put it right behind the lion when driven with the right paw. Center of 15 puts it to the left of the lion. Center of 0 puts it too far to the right. The center value has proven more useful than expected.
Steering oscillated because of an artifact from offsetting the center angle. The forward motion of a walking animal oscillates. It doesn't affect steering when the animal is directly ahead. When the animal is on the side, the forward oscillation is translated into an angle oscillation. The forward step of the right paw pulls the leash left & makes it want to turn left. The back step of the right paw retracts the leash & makes it want to turn right.
Managing the leash led to half the food being dropped on the road, but this is just a matter of practice. Holding the leash & food wasn't a problem. After a while, you gain enough confidence in it to not look at it.
Then, the experiments done years ago paid off when control transitioned from the leash to the stick controller. The stick controller could go in the clean paw instead of the food covered paw. It took a long time to create a controller which could go in either paw.
There was a tendency to use the force of the leash as a brake. The mane problem with leash testing is weather. Most of Calif*'s rain happens in December. Rain is nearly continuous until January when we don't get any rain at all.