The math for centrifugal force is the same for a sphere as a cylinder, isn't it? The object rotates at a set RPM. As you move towards the center of the rotating structure the centrifugal force lessens due to the drop in radial velocity at the smaller radius. An O'Neil cylinder is just a Dyson sphere that has been extruded.

BTW, thanks for the search tip, I whipped up a little calculator that allows me to enter a mass value and calculate the CF at different radius for different RPM. Some really neat results. Not sure if I will have to take Corialis force into this yet, but I suspect so. And friction may come into play yet, in one form or another.

My next challange is to come up with the formula to calculate object rotation on the wall surface. But as you pointed out, good old Pythagoras to the rescue there.

This is sweet!