I dont think I am understood correctly.

I just want to cover the surface of this stage....it is like a riser ....one
step up from the floor. it comes out from the wall and has a constant curve
(matching soffit above at ceiling). Horizontal floor surface on this stage.
The front edge is curved at a constant radius. I am thinking I just use
hardwood flooring and trim the strips off at my radius and wrap it with a
thin hardwood molding.

Just nail planking on top of it so that it overhangs by an inch or more, and
then
trim it off to fit with a router bit.