On Saturday, May 10, 2014 10:49:57 PM UTC+12, wrote:
3) Whether you include the wingtip clearance in the calculation or not, the total height loss doesn't vary all that much between 30 and 60 degrees of bank - about 6 feet of difference for the center of the aircraft and only a foot or two of difference at the lower wingtip.

I've added the wingtip calculation.

The bank angle that keeps the wingtip the highest varies with the wingspan .... it's about 39 degrees with 18m wingspan, and 41 degrees with 15m.

The difference in wingtip clearance between this 39º or 41º bank angle and 55º is 1.8 ft for 15m and 2.7 ft for 18m.

If you're low enough for this to make a difference then you probably shouldn't be turning back :-)

I still think the horizontal displacement from the centerline is the biggest factor.