Bruce,
Thanks for an excellent presentation of heights, weights, and spring compression.
The load transfer results are in very good agreement with both theory and other scale data.
The numbers show a consistent load transfer to the front axle of 60# per 1/16" of compression.
That indicates the 1/4" of compression reported to have been suggested by Andersen would correspond to a front axle load transfer of about 240#.
Renojack's recent measurements indicated a front-axle load transfer of 360# with a compression of 13/32" (assuming an unloaded spring length of 2-15/16".
This corresponds to a load transer of 221# per 1/4" of compression. So Renojack's indicated value of 221# per 1/4# agrees well with your 240#.
Based on this small amount of information, I would guess that an Andersen WD hitch would adequately compensate for front-axle load removed by a 400# tongue weight if the spring compression is to be limited to 1/4".
I it would be good if Andersen's could let us know how much compression is acceptable.
Ron