Fleery, mate. Firstly, as for the statistics, do you have them readily available or can you point me in the right direction?
Secondly, most posters here know far more about the aerofoils than I ever will. That said, your argument about a 172 on late downwind at YMMB being able to reach the threshold is probably fair enough. Let's however transpose that to a similar aircraft at YMBU or YBDG on an early or mid downwind position - at night. See my point? For ab initio circuits in day VMC at a training aerodrome I see no problem with keeping them reasonably wide. After that, the closer the better in a SE A/C - within reason.
Cheers.
