Am I totally nuts or just a bit off?

I think that you are totally nuts. The Shure, designed for 78RPM wide grooves, not mono LPs, has a stylus with a diameter of 65 um. The correct size mono stylus for the mono records that you are playing is around 25 um, but not any larger than 35 um. I believe that you are risking groove damage using this sized stylus.

I think that, if you get a mono cartridge with a properly sized stylus you will enjoy your LPs much more. Grado, Ortofon or even the Denon 102 should fit the bill and not break the bank.

Schubert, the N70b has a .6 mil stylus, which is about 15 um, it also has the conical profile that you prefer. It will certainly ride lower in the groove than the M78, and some of the results will be related to if there is any groove damage in your records, and in what part of the groove that damage occured.

Why not give it a try and report back with your findings, pro or con? It is certainly the preferred size for the records that you are playing.

Schubert, glad that you are enjoying the change. I love Dakota Staton as well.

The early stereo effects - vocalist in one channel, band in the other - drive me crazy. I have been enjoying some mono Nancy Wilson and Jo Stafford of late.