I have a Marble Madness, but its not at home, its in a warehouse...
could go there this weekend and measure/take a photo... I dont have a "whatever it is called in english" to measure the radius though.
But i can measure to the beginning of the radius from both ends and I should be possible to calculate I guess...
Unless someone already has the measurements you need.
Is U.S and Ireland version the same? Mine is Irish anyways.