I flew a Ka-6 a few years ago. Except for the extremely tight seating,
I loved it. t was one of the nicest flying sailplanes I've ever been
in. The truth is that cellulose fibers (wood) have no set life span. I
wouldn't be afraid to buy either of the wood ships you've mentioned. I
would not be afraid of the Nugget, either. I built most of an HP-14 and
think they're fine ships. I have a Pik-20B that I think does pretty
well in light lift, with the flaps and ailerons dropped 8 degrees, it
does nicely in 1 to 2 knot lift, if I was patient enough to stay in
it... I usually make a few circles and go bombing off looking for 5+. I
have been able to stay with just about anyone else in thermals and do
better than most I've encountered.

Enjoy,

Jack Womack