I have not turned around at our airport during a tow, but we did it out
at the Alvord Desert! We made a very wide turn and ended the launch
back at camp where we had started. We regularly got to 2000ft to
2500ft without having to turn around, but we have miles of dry lake to
use. The tow line back releases as soon as there is any slack, so I
can't see any way to turn around or back up at our airport, but I tried
something new the other day that did work very well. Given that we
have a set distance to tow here, I figured that if I aggressively
zigzagged the sailplane on the way up, I would effectively get a longer
tow. It worked very well and I got higher than I've ever gotten at
this airport, 1500ft agl. Our weather has not given us another chance
to work on perfecting this technique, but I think with good
communication and coordination between the pilot, the driver and the
winch operator, and a stronger wind, I just might be able to get as
high as 2000ft agl.

And on the subject of towing heavy gliders, I have winched our 2-32
with 3 people in it, I think we were probably close to 1400lbs, and it
worked surprisingly well.