Actually, yesterday, I was playing around with the repulse control and came up with a repulse/spring top control too and it looks almost the same as Mark's I bet it's inferior to Mark's original one, but still thought it was neat haha
I really doubt that it was inferior, but I actually think that it's quite similar to what I did, apart from using the 'Repulse Control'. Want to put it on your upcoming release too?