ASW 20, ASW 20B, ASW 20C DIFFERENCES

The only place I have found to research the differences between the
above ASW20 glider models is on the Sailplane Directory website. From
what I can tell the B model differs from the "A" by a slightly heavier
airframe, boundary layer control blowholes on the wing, a higher auw,
and different airfoil. And as far as I can tell the C model seems to
have the same airframe as the "A" except for a slightly modified
cockpit, whatever that means, and the same boundary layer control and
airfoil as the B. I also believe the B and C models have different
(less) positive flap settings than the "A". All are certified in the
experimental category.
Can anyone corroborate/elaborate? Also, where can I find
airworthiness directives/technical notes on the ASW20? They are not
available on the FAA website for this model glider.