Why I'm not using construction lumber for my bench

As Nicholson observed, the thicker the better.  A criticism sometimes made of the Nicholson bench is that it is springy and light.  I think this can be addressed by using full 2" pieces and by stiffening the torsion box.  After using his Nicholson bench for a year, Bob Rozaieski said that, if he had it to do over again, he would make the top a full 2" so holdfasts would work without gluing blocks to the underside of the top.  A good compromise would be to make the base out of construction lumber and just make the top from full 2" higher quality lumber.  But, I decided that I would either use reclaimed lumber, which is often available in my area, or go to a custom sawmill for all the material.  As it happened, I stumbled onto what I regard as a great option.  A custom sawmill in my area had some kiln-dried almost clear vertical grain Douglas Fir that had been rejected for millwork because of stains.  I got it for less than $3 per board foot, much more than construction grade lumber but worth it in my opinion.  The pieces are dead flat, sanded and a full 2 inches thick.  Because they are vertical grain, I hope that the bench top will be very stable.  And. ...I like the way it looks. This lumber says Oregon.  It's acclimating in my shop now.  Time to settle on a design.