Any electronic geniuses here?

Again... not a genius but I've designed a few phono amps. Lundahl make nice MC transformers, they also have quite a bit of technical info on their website. There is also this handy tech note that provides guidance on setting up the input impedance when used with an MM stage.
If I remember correctly the data sheets for the trafos are missing some information to do the calculation for yourself but I can probably dig out a spreadsheet I've used for the calculations in the past if you can't find what you're looking for in the tech note.

https://www.sowter.co.uk/phono-cartridge-transformers.php

You will find exactly what you want here. 

Ralph said:
"If loaded too lightly it can ring, "

This can be a danger, or an area of mistakes, as we can mis-load and live off of the ringing, which exists as temporally shifted energies. (one way of explaining it)

We can mistake this noise for detail and lose actual detail in the spray of noise. It crushes dynamic range but leads to an impression of detail, to those who seek easy answers and use their minds to fill in, and are not actually listening. It is exactly why we have people who don't hear what power cords do or what rca cables do or what fuses do, and so on. 

FYI, a core function of how the ear/brain works, is to fill in. Look up speech recognition, in time. We preload sound patterns via the ego loop, to speed up recognition, and some people are so bound to that, that they cannot hear what the equipment is actually doing. They can't shut it off and listen for real.

Listen for it. Try to isolate that aspect, via actual listening and learning. 

It is a very critical thing to understand, it leads to a far greater dynamic range in a system as a whole, once a person ’groks’ it. Decisions in system building change to accommodate it, and then we start building our systems properly.

Again, sincere thanks to all who responded.  I have opened all the included links and will go over each.  As I see we are drifting toward the inevitable opinion pieces it's time for me to unfollow.  BFN

Would it not be wiser (and maybe even cheaper) to buy an MC phono preamp that you can directly connect to, instead of going thru a transformer ?