Q.: How do you avoid the little shapes that look like pointed ovals on concrete surfaces? Would a paint or coating on the plywood forms take care of them?
A.: You must be referring to plywood form marks from what are usually called boat patches in the plywood. The plywood manufacturer stamps out these boat shapes around knots in the surface ply and then inserts precut patches of the same size and shape. The boat patches make the surface of the plywood smoother than if it contained the knot, but the patches aren't pretty. B-B Grade plywood, or any other grade that contains boat patches, should not be used where this kind of imprint on the concrete surface will be objectionable.