We all are very happy your mount guides exceptionally well Lewis, and I’m just stirring...but it would be interesting, if it is not a big trouble, to see your guiding graph in arcseconds, if only to satisfy my vain curiosity.
As for Mach1, I guess many users were succesfull in guiding heavier telescopes on it, thus the recent change is the specs
I do not expect to upgrade my 4” in the next decade anyway, as I need to first grow a new kidney (yes, as a Chernobyl surviver I can do that), so I did not pay much attention to Roland’s announcement.