I think your concern about the Miele combo head is correct. I have a large pebble tile floor in a bathroom and the Miele combo head clacks and bumps going over it, the single large rear wheel exacerbates the uneven surface. I also think that a Miele vacuum would get faster wear on this kind of surface.

Instead I'd recommend a Henry 160. Henry is very very quiet about the same noise as a Miele and Sebo. Henry is more robust made for commercial use as well as residential use. I think the large hepa bags would do better and Henry can stand up to more knocks.

Henry comes with a similar combo head so instead I would recommend the Wessel Werk Turn and Clean Brush. The WW Turn & Clean has no wheels so it doesn't clack over uneven surfaces and it has almost a double pivoting neck so it has an amazing swivel. Another option is the Hoover Floor Brush this is a Wessel Werk D360 equivalent, it's a lightweight soft floor brush with wheels on the side so it doesn't clack the way a combo brush does.

Thoughts?