I don't think you can install a throw out bearing backwards ( can you?
)
I've seen this problem before.
I removed the threaded rod and made a slightly longer one so the free play would be taken up. I'm thinking maybe your flywheel has a lot of material that's been removed over the years and it's causing everything to be beyond the range of adjustment that you currently have.
If everything gets too worn then the clutch fork will bottom out against the slot in the bell housing when you push the clutch in. This is an extreme case and you'd be looking for another flywheel before it could be fixed properly.
I hogged out some aliminium on a bell housing once just so I could make it work. This was 25 years ago on a 220SEb coupe so maybe that doesn't count too much.......