Does a glider perform differently in an updraft? *Seems like it, at least in the degree of back stick needed to maintain a circle. *This is no surprise, I'm sure. *The "updraft" contributes to the force needed to reduce the downward acceleration of the glider, so less lift force is needed for the job, so less increase in AoA is needed.

An updraft is a velocity, not an acceleration. What you are saying, is much like saying a glider handles differently in a headwind, crosswind, or tailwind. Remember the famous "walking slowly down on a rising escalator" analogy-- does it feel any different as you walk downward, on an escalator that is rising than on an escalator that is stopped?

All unaccelerated reference frames are equally legitimate-- it doesn't matter whether the escalator is stopped or moving up or moving down, it feels the same to walk on in each case. It only feels "funny" for a second or two when you step off the escalator into a new reference frame.

Food for thought...

I'm at a loss to explain your perception. Nothing comes to mind that would create that illusion-- unless it's just that when you are rising rapidly, you relax a bit and are no longer so worried about maintaining the absolute minimum sink rate relative to the airmass.

S