Seal the concrete with a penetrating liquid and/or plastic sheet. Lay
down tubafour sleepers (12 or 16 inch centers depending upon weight of
machinery) with insulation between. 5/8 or 3/4 T&G OSB atop that.

No No No. OSB will support you but you will have A b*tch of a time sweeping
up sawdist It's just not smooth enough. I have 3/4" T&G A/C plywood over 16"
centers painted with two coats of oil-based enamel deck/floor paint. The
paint makes the floor *much* more sweepable.

A
light color primer to enhance the lighting.

I found the basic gray to be too dark, so I bought a can of white and a can
of gray and mixed them.

-Steve