Answering an old post. Sorry it took so long.
What happened was I was talked out of it by my tech, who was very patient in explaining why this would be a fool's errand. What he did do, however, was adapt a carbon ribbon Selectric 1 using the carriage of a carbon ribbon machine, and I am as happy as can be. You see, the whole point for me was to keep the "playability" of the Selectric, but with cheaper ribbons. Carbon film ribbons have become way too expensive around here, and I use typewriters for drafting, it didn't make sense to spend all that money on ribbons.