Fascinating thread. Perhaps two systems at work here? The US system seems to allow lower circling minima and much tighter circuits (TERPS?) Must you be visual with the airfield at all times?
The JAA circling approach allows you to lose visual contact with the field as long as you stay within the circling area and above circlng minima for the sector you are in until you become visual. 5.28 nm for Cat D aircraft. FMC used for wind assessment mostly. How do you stay visual in a jet, downwind 3 or 4 miles from an airfield?