So......this can't be done. Got the die, cut and tapered the rod, couldn't even make a shiny line in it. 100% total no-go. The excellent gentleman at Jacob's surmised that Ludwig cut the threads, and then tempered the steel.
Plan B was to get 12-24NC coupling nuts and "lengthen" the 30s T-rods with some 12-24 threaded rod [they came off a 12X25" bass drum]. However, the excellent gentleman at Jacob's informed me that 12-24 is quite rare these days, not in use much, and they don't have the coupling nuts. And here's the thing - if they don't have them, nobody does.
Plan C is running 4 single tension MIJ rods I have off a 14" bass drum through the insert-less casings on the bottom, and four-a-side originals on top. This will work as I've tested the rods through the casings and they make it through without being bent.
Plan X is finding 8 more originals, and as we all know, that ain't happening. A couple members here warned me these parts would be hard to source, and to be honest I kind of brushed it off. Had I known it would be impossible, I wouldn't have bought the kit. Nor will I ever buy drums with missing rods ever again.
Learn from my mistakes! :)
Mitch