Thanks for all this great info!! I appreciate the mass calculation it makes things more clear.
I think the Nagaoka's or Audio Technica's look good. The AT's give me the most choice and seem to be in the range of compliance. I think trying to find a cart that is a little on the warm side will be a great match. The 5650 has triode like qualities but also can be very quick and detailed, so a little warmth won't hurt.
I'm interested in the Pickerings but a little hesitant to get NOS stylus. Also, does the brush make a difference?
High output MC's I usually would not shy away from, I enjoyed a Denon DL-110, but I'm concerned that they would be too strident, although that is a statement made naively.
What about old Empire or Grace cartridges?