Making a 36" x 36" Canvas with home-made stretchers

I'm preparing a canvas to paint a picture for my daughter of Cherry trees in full bloom. I ripped a 2x4 length wise at an angle. The angle was set at whatever angle would split the 2x4 in half lengthwise.  No precision here!  Don't need no stinkin' rulers!  :-)

The  bottom dimension is 1 1/2 inches (the thickness of the 2x4). 

The left vertical dimension is (approx.) 1 3/4 inches

The right vertical dimension is (approx.) 7/8 inch

The "lip" at the top is MAYBE 1/8 inch - the width of my table saw blade kerf.

I used corner clamps to hold the corners square while I put two (2) three (3) inch screws in each side of each corner. Sorry I didn't think of making photos until I had the canvas stapled to the stretchers. My bad!

I have wrapped the canvas over the stretchers and stapled on the inside surface of the stretchers. Gallery wrapped?

My Boxer, Simon, inspecting my progress. Being a dog of the male persuasion I had a fleeting concern that he might want to "mark" it. But he's a really smart guy and only sniffed it really well!

Casey (our other boxer) and Bella (our miniature schnauzer) were NOT interested at all!

The canvas in my studio. The first "study" painting (11x14) is behind the top middle of the top edge of the canvas.