Mozzie, I have the best success at 3:1. After 4:1 it just becomes too watery and I no longer consider it a gel. I spray the wheels directly, but to get behind the spokes, I use a brush bent in the shape of an "L" and I will spray the brush directly and start cleaning (since it is almost impossible to spray onto the back of the spokes). CG gives us the impression that Diablo can and should be left to dwell before agitating, but in my experience the product starts working as soon as you start cleaning. Similar to P21S Gel, you have to use the appropriate brush(es) to agitate the wheel.