On Monday, February 10, 2020 at 1:00:42 PM UTC-8, Martin Gregorie wrote:

If the OP fits an ASW-20, he'll also fit an ASW-19 or a Centraire Pegase.

The 19 and 20 used the same fuselage moulds....

As a caution, there's a lot more to cockpit ergonomics than the fuselage shape. The detail design of the cockpit, including the location of the wing and undercarriage anchors and control stick mechanism, can have a substantial effect on the effective anthropometric range. I know that the Centrair products started off as licensed copies of the AS gliders, but their design remained relatively static while Schleicher was continually incorporating minor changes.

As a general rule, the later versions of any particular type are often better than the earlier ones, as they tend to accumulate minor improvements that make more cockpit volume available.