I would think an ultrasonic inspection could get
a good enough picture of the undulations to know
if it's serious. Problem is what deviation from
ideal is acceptable? If anybody knows a glider
pilot who is in the USAF they could check with
the NDI Lab at their base and see if someone
could inspect the spar. Long, long ago I was an
AF NDI Technician and we X-Ray'd car batteries,
mag particle tested cam and crankshafts and would
have jumped at the chance to inspect a glider wing.

Nothing they did could be official, but for peace of

mind it might be something to try. You might get
some new students at your club. I first saw a soaring

site when I was stationed at Zweibrucken AB in Germany.