I love your design and execution! This is a fantastic set up!
I have to say, and partially in answer to the question above, I DO NOT like your choice of standard grade AC (or worse) pine plywood!
You should treat your time and effort better by simply paying a small amount more for some decent stuff that will actually take a finish and not be full of patches and knots and rough yuckoo surface. It will offer a much nicer end result and is easier to work with as well.
CCF, At your local Home Depot you can find reasonable priced "sande" "poplar" and "Birch" ply, and for a bit more you can get Oak and other more high end woods. For the record, all plywoods at Home Depot are fairly "cheap" in both price and quality even when you move into the "cabinet grades" like those I am recommending. real Cabinet grade quality will cost $80.00 or more a sheet, the stuff at Home Depot will start at about $38.00 for the 3/4" poplar
I love to work with the birch and sande, both light colored blond woods that take any finish beautifully. The Poplar is only available in 3/4" and DO NOT USE if you want to paint it
For Urethane of staining it's fine. All three are hardly a few bucks more than generic rough AC pine/fir ply.