I have been reading this thread with great interest. I have found the argument of "the rule of thumb" settings, as recommended of some, and the settings as recommended by manufacturers (or close) to be of greater criticality.
I own a JC Allerts MC1 and it is emphasised by the manufacturer the criticality of getting the settings correct, or you will burn out the fine hand wired coils like a light bulb filament. With in mind I also use a Audio System TE MC phono stage to accurately load the cartridge.
Perhaps this shows that there is greater leeway of load settings in more common commercial cartridges than with others? A.

