I thought I might participate into this discussion. Reading all these threads, just wanted to add that I too learned rolling circles (not harriers) using elevator only and I ended up getting them done pretty smoothly but not perfect. The key to do them smoother is the speed. Faster you go less input you need and less wobbly it gets.The only problem is there is that wavy up and down motion as it rolls which you almost can't get rid of. Then I learned to use rudder and that I must admit changed whole appearance of the maneuver.
The speed is also key factor for KE. Some people don't need to use much rudder particularly pattern planes 'cos they fly much faster. You know that in harriers you need all throws you have on rudder and elevator to keep the attitude of the plane 'cos it moves slowly.
UBy, I haven't seen your video but I hope you mean rolling circles not rolling harriers. Honestly, I just can't imagine how you can perform rolling harriers with elevator only.