gypcrete over high density mineral wool over concrete?

Hi Folks, Background: I've got a 10'x20'x9' garage that is being converted to an office with anticipated future use as a control room adjacent to a 20'x20'x10' studio. I'm trying not to do anything now I will regret later if/when the studio materializes. Question for the control room side: The floor is a poured slab, not sure how thick and there may not be a vapor barrier underneath it. I would be happy to live with the concrete floor except that: a. It's not thermally insulated b. It's not quite level, probably purposefully sloped for water runoff. So to fix both issues, I'm thinking of putting a layer of plastic vapor barrier, a layer of high density mineral wool or fiberglass, thickness tbd, for thermal insulation, then gypcrete to level and smooth as the final floor, stained or painted or perhaps tiled. Thickness tbd. It looks like the difference in thickness between the shallow end and the deep end is as much as 2", so I'm not sure gypcrete is the appropriate material. Is this a sound idea? Suggestions and details more than welcome. James