Silver-I wasn't going to have a spinner, I was just going to substitute the trackball. But, I had allowed space on the removable CP on level two in case I changed my mind later. My aim is to sort out the spacing properly when I start cutting up cardboard so I will fiddle with P3 & P4 then and see how it feels.
Yeah good call Walls83, I will definitely put a slight slope on both CP's.