You are welcome, I am relieved to see my measurement agrees with that Japanese chart! If you are going to build your own attachment, the use of a body cap to mount the lens might be useful. The pinhole adapter I made can be seen here, it would probably be possible to use some plastic pipe fittings to create a crude lens mount. You do have to avoid anything that extends inside the camera body very far, as it could hit the mirror.
WOOOW!!!! That's really GREAT article! Thank you for it!