Just a little bit of info for you... a piece of 1" x1" wood will not withstand the tension of stretching canvas without bending.
The most common size is at least 1x2 which really isn't that big anyhow. As long as your stuff is small you should be ok. But as soon as you try to stretch canvas over 16x20 or so, you will have a problem with the sides curving inward making it look amateurish as well as not fitting into a frame without showing a gap.
Over time, it will warp and twist and look cheap and amateurish. I get this homemade junk in all the time asking me to fix the warped canvas piece. The only way to fix this is to throw it out and do it right as it should have been the first time.
Just because you can buy wood doesn't make it a good decision. By the time you get all done adding on that little half round piece, cutting and assembling and adding interior supports so it doesn't bend inward on you, you could have bought the type with the wedges you are lamenting you wish you had.
Seriously.
When cut to the proper length, your 1x1x16' sticks WILL make great kindling for the woodstove.
Agree about the size of your materials 1" is marginal at best.
I use 1 1/2" and 2" deep bars and only the occasional 3/4" depth when float mounting
Everything about the heavier bars is a plus. Stronger,and a great look.
The amount of time needed to do what you are doing does not save you anything.
Just call Decor Moulding in New York. Or a half dozen other companies that sell the same products.
You will have them in 2 days UPS.
I think the 7/8" stretchers are around .45 a foot and the 1 1/2" bars can be had for about .50 a running foot. (When on sale.)
Material from Decor for a 20 x 16 frame will cost you about $3.00 Thats pretty darn cheap.