and realized that in both these videos there was a slight leg sweep/trip or at least the legs were positioned in a way that prevented the leg from posting. I haven't tried this yet (going to do so asap).
in my experience from getting thrown by Sensei is that the most effective variation of udekimenage is by moving your whole body (or mainly the hip) toward uke with your upper arm somewhere between uke's upper arm and elbow. also make sure that uke's hand is straight, not bent. and when you throw him, use your hip. I had it done to me a few times and the result is quite satisfying. the forward projection I got was a big one.. I don't know if it was just my instinct to ukemi but I did.