Reply #5: You don't need that much R value insulation

[bahrbearian]

R19 will work just fine, put it up against the flooring, hold it in place with ridge wire (like a coat hanger) cut a 1/4 inch or more longer than the opening in the span between the joist, bend the wire to fit between the joist, push it up against the insulation and release. Put one every 2 feet.