1. Your foot is about 6 or 7 inches long from the heel to the balls of the foot.
2. By landing on the heel and transferring your weight to the balls of your feet you move your axis forward (or backwards) by that distance, assuming that you keep your axis over your foot.
3. Your follower is doing the opposite of what you are doing when she is walking backwards (landing with weight on the balls of her feet first and transferring weight to her heel) as indicated by your lead.
4. If you try and put your weight on your toe first (as a leader) you are effectively telling your partner to put weight on her heel as well as stopping the indication that you want to continue forward motion. If that is what you are trying to achieve this is one good way of doing that.
5. Followers should use their heels (as opposed to keeping weight solely on the balls of their feet all of the time) to avoid serious foot problems and possible injury.
6. Pivots should be done with the follower while her weight is on the balls of her foot.
7. As a leader you are responsible to make both of these things happen as required for what you are trying to lead.
8. During single axis turns (when the follower is keeping her shoulders with yours) the follower needs to have her weight on the balls of her feet while her axis is leaning away from the axis of the turn, knees must be bent at least slightly for these things to occur at the same time.