2 x 6 T/G decking

We just finished our frame, Doug Fir with 6 x 8 joists, 3' OC. We are using 2 x 6 T/G Norway Spruce for the decking. We are planning on putting a sound barrier on top, probably cork and then regular T/G hardwood flooring on top.

Is it necessary to blind nail and glue the decking to the joists or will nailing alone be sufficient?

Also what finishes do you recommend for the Norway Spruce. I have heard that using a penetrating oil works well. Any comments on what brand?

Thanks

Haz

glue helps keep things quiet, but if you are laying a sound proofing layer above the spruce, the glue may be a bit of overkill.