I finally started following my TimeZone School Level 1 course to disassemble an HMT movement. The HMT 0231 is very similar to the Fontainemelon calibre 97 (FM97). The big difference (actually fatal ) was that the screw holding down the ratchet wheel on top of the mainspring barrel was a left-hand thread.
The school instructions say the screw on the ratchet wheel is a normal right-handed. (turn screw counter clockwise to remove)
Why would the HMT copy of an FM97 be different?
(or am I just confused?)
P.S. I wimped out on removing the trishock assemblies.