You should be able to slow your gear more than is shown in your video. The gear does react more slowly at first because the postion it starts in is where it has its least amount of leverage. My gear reacts the same as yours, but more slowly. It takes a very small turn from closed on the "Varable Rate Control Valve". I'd keep working the wood shims until you get the gear to lay flat on your rails. Using epoxy as shim material sounds heavy and messy to me.