I am putting asecond layer of sub floor over 1/2" ply on an in-law apartment over a garage. I am debating between types of sub-flooring to use. I could use ply, but OSB and MDF are less expensive. The fininshed floor will probably be a wood floor, either Oak hardwood, bamboo, or peel&stick oak strips. Is one any better or worse as far as movement, surface porosity (for the peel&stick), or strength per sq ft? Any guidelines on thickness i.e. 1/2 for a total 1" thickness? Thanks!