Davis: I read your post but did not have experience with (or knowledge of) that brand of case. But in my experience, most alto saxophone cases will accept most alto saxophones, save for the larger/longer-bells of Cannonballs, Buescher TH&C and low-A horns.
Most every alto made in the last several decades are about the same size and design as a MKVI. Even the older horns with right-side bell-pads and the 1920's models with split-bell-pads seem to fit in the generic cases I've owned (mostly Pro-Teks but I've had others). I have done exactly that with a variety of altos from 1920's to modern.
You didn't provide a link and I didn't search out those cases you asked about. But maybe if you sent them a query, you could find out for sure from the company that makes them. DAVE