I was thinking, instead of using a ring, use a set screw. Just offering that, since you were talking about having to take them apart to machine. You have more tools and skill than I do, so maybe it's no big deal like it would be for me. And I detest that snap ring. Tote Gotes are held in check with a retaining screw, as are some others. The method you are describing is far more elegant.
The lowers would still slide, but a welded-on stop could be added to prevent the entire lower end from falling out during some sweet jumps.
Also, when I replaced the bushings with oil lite I got off an Ebay vender, I had to machine them down to fit. LOL, just disregard if I am not making sense.