The PW-6 takes min pilot weight of 120lbs in front and up to 441lbs in
two seats with no ballast requirements. Spins too.

For the ASK-21 is a "spin-weight" available which can be installed on
the rudder. Of course you have to weigh the pilots before deciding which
weights to add to the glider.

But then you have a very nice trainer with which you can also train spins.

CU
Markus