Mud Sill placed off-center on Footing

[buildhome]

I have been working on building a 20x30 house on a frost-protected slab. The plan for the slab was to be a thickened edge, monolithic, Alaskan slab, 2 feet tall with 16" wide footings and two 1/2-inch rebar top and bottom and a 1 foot wide by 8 inch deep grade beam down the middle of the 30 foot length with two 1/2 inch rebars.

Now that I may be having trouble hiring out the pour or finding enough help I was considering doing it in two pours by doing it like a stem wall. I have the exterior forms in place and am thinking of putting in an interior form to pour a perimeter stem wall which will be the same 2 feet tall and 16" wide from bottom to top and then floating a 4" slab inside the stemwall without tying them together with rebar. The one possible hitch I thought there might be is that now the mudsill will be placed on the outer edge of a 24" tall by 16" deep footing/stemwall instead of in its center.

Will this off-center of the weight of the house be a problem? Any advantages to either of the two methods (stemwall vs. monolithic)the stemwall? If the off-center is ok, what about differences between suspended slab (poured on a ledge in the stemwall) vs. floating slab?

Thanks