Knees to elbows become much easier with the little pull you talk about. I think proper form requires that they be performed with completely straight arms (therefore eliminating the pull). I started out doing them with some bend in the arm and making sure I got contact with knee and elbow and gradually worked on reducing the elbow bend while maintaining knee and elbow contact on every rep.
I guess the alternative of maintaining straight elbows from the start and working at getting closer and closer to making knee elbow contact would also work. Also I know people who have had success allowing themselves a little jump off the floor on every rep to begin with.
I would recommend going with a method that allows you to get through the reps in a workout like the one above while maintaining a high intensity of training combined with adding some strict skill practice to your warm up.