Great find there.
I love it when someone picks up on a comment somewhere, tries it out and gets a result.
I hope this provides new possibilities for screen stability.
(Im also glad that you found a use for the reserved/unused ST mode; PPera almost bit my head off when I asked about the TT ones, so thank you! )
Anyway, Im looking forwards to the demo release for this technique. I have a MST ready, with several CRTs available, including a 15-31khz multisync/scan, so should be able to test the demos for any sync bending you do.