On Tuesday, October 4, 2016 at 7:32:34 AM UTC-4, RR wrote:
I used to fly with a built in margin, I have now set it to 0. I think it was set to 800ft, so a normal pattern could be flown when I got home. Then on day my final glide got washed out (literally in the rain) and I really needed to know the correct arrival height. Was it 700ft reserve, 1000ft, what did 300 under glide realy mean? Now when I most needed the correct info, I was doing mental math. I switched that day.

RR

A good friend and tremendous wit, Tony Benson used to have a great saying. "When the magic reads zero, I open the canopy and step out." His point was exactly yours Rick - trying to remember what margins/cushions etc he had set up sometimes required math at the least convenient times.

FWIW, I have the two glide amoebae (amoebas?) on the Clearnav set at 0 feet (Kellerman calls it the Crash Line) and 1,000 feet. So, I can instantly get a feel for where every known landable field sits relative to those two values.

P3