Jumping In With Both Feet. DIY Ribbon Planning.

I'm not pioneering anything. Lol. Just a dude following a few vids and a pdf.

I am gonna need to figure out a different donor body, or make an enclosure for it. The frame is bigger than the head basket of the cheapie donor. At least all isn't lost: the cheap donor came with a shock mount that is very similar to the one my AKG came with, and a foam wind screen. Lol. The AKG is having problems, which is a bummer, but I can reuse the flight case from it. The frame is also wider than the AKG head basket, as I thought about using that body as well. I don't feel like narrowing the motor frame. Lol.
I think you are venturing in where only big companies like Shure brothers have perfected the process. There are lot of other things to do rather than try to build one of these and I myself would not venture in this area. Some of these large companies like Neumann and Shure have large perfected facilities to wind coils and that which you will not match in a basement or garage. Something about mics and especially condensers is the control of the coil winding and maintaining the correct dimensions as well as stray capacitance and inductance.
skywave... would hate to rain on someone's parade of raining on someone elses parade....🤪🤪🤪 however i believe you have missed the point of this DIY🤯

for one ribbon transducers are incredibly simple devices to build, with ZERO coils of wire in the motor assembly,
they operate under the principal of current being induced into a pleated foil ribbon suspended within the flux of two magnets and sent through a 20-50:1step-up transformer
(not exactly rocket science)
being the only "complicated" component in a ribbon mic, this step-up transformer could be tricky to diy ,but certainly is not impossible
furthermore the author had stated that there are off the shelf options they would take advantage of...
(go with the lundell btw👍)

although ribbons don't have a great deal of output, with a proper mic preamp one can capture nuance and detail and clarity that rivals some of the most expensive large diaphragm condenser mics meticulously crafted in labs not unlike NASA, in spite of a deceptively crude design

sidenote- Royer labs, one of the widest known ribbon producers worldwide is much more like an artisan/craft shop than a "large precision facility"

anticipating good things from this build
keep up the good work !!!
and above all,
have fun with it!!!
You could avoid the transformer problem Rev' by making the mics active. Douglas Self has an ultra low noise pre amp design for moving coil gram pickups. These range from 3 Ohms to about 50 Ohms and you can use paralleled transistors to get really low noise levels. I am sure the designs could be adapted to ribbon mic usage. Might need a 1:1 or 1:3ish traff but they are MUCH less problematic to source or make than 1:50!

Or look at our chaps Msssrs Sowter? They make a vast range of transformers. I have one of theirs, 1:4 booting a Relso RB 30R jobby to about the voltage of an SM57.