just an update to this thread if anyone is wondering. I have not done rigorous standardized testing of the 50mmC and 65mm KL lenses, but I have used both extensively in the last little while. My impression is that the 65mm KL is a much better performer - pretty much no CA. Also both lenses are very sharp in the plane of critical focus, but the 65mm KL is sharper for things that fall into the planes of acceptable focus according to the aperture's depth of field. That is awkwardly put by I didn't know how else to say it.
Anyway I am going to keep the 50 because it has come in handy for situations where I specifically needed the extreme angle of view, but the 65 KL will be my go-to lens from now on. It is fantastic.