I didn’t think they’d been available for a few years, but there might be a few kicking around somewhere.

Just keep in mind the one Andy used to get good results with was the $1600 variety.

And then...... the $1600 job on the 400-3 was better than the $1600 M1........ so I’m not sure how this is a step toward.

But....... the interesting test would be to try the M1 without the $1600 job, and see how it compares with what you have.
(It’s not what I would do...... but I’d still think the results were interesting)