It'd be great to see something similar done that includes a Tessar. There are always those who prefer one to the other, claim they are the same, prefer one's bokeh over another etc. A real-world methodical Tessar vs. Planar (vs. Tessar-Tmodel version?) would give people a nice set of actual images to look at.
The Xenar is Schneider's version of the Tessar.It should be quite similar.