Micro Rotor Automatic

May work better with a gold or platnium rotor!
Some of label companies would buy ebauch movement & re - work them or if you like fine tune them & put in gold rotor a weight. You can see some current $$$ models do still use gold. Some not so, [ Hum! ] honest repairers would swap out the gold rotor for a standard isue one. Before glass back cases, who would know.
Prior comment, not realy true: Automatic & calnder mechanisims are considered complicated.

My Buren Super Slender microrotor

It's a handsome piece.

Today I think you would have to look to Patek or Bvlgari for a modern micro-rotor... Well done Buren.

Another Buren😀

Photos by Richard Askham while servicing my Hamilton chrono-matic



Rich did a very fine job on this which had some issues.