wrote:
Take the time to put it in the fin. This keeps it out of the wing
root wash and will make
the variometer reflect what the glider is doing instead of how it
responds to effect of gusts
on wing root.
It may be easier than trying to work as far behing wing root as it
should go.
Just put one in a K-21 fin and it is MUCH better than aft fuselage.

Johnson did do testing for both the 6/05 (and an earlier 4/98) article
to determine an appropriate location and height, and:

the author's flight testing indicated that its performance
was just as satisfactory as a tail fin mounted standard
factory built T.E. probe on a Ventus A

The probe was placed on top of the fuselage, just ahead of the aft drag
pin bulkhead, not the middle of the tail boom as is typical of K-21s.
Maybe it's as good, maybe it's not, but it sure beats cutting holes in
the fin...

Marc