Your plans are industrious. For your number of plants (I'm guessing about 80.), it may be a lot less work to just inspect your plants every couple of days, and pick off the eggs and tiny hornworms. When you get them early, it's unlikely to become a significant problem. As JBD points out, even with the canopy, you'll have to inspect them anyway.
Sections of 15% shade cloth can be used as a floating row cover for the first few weeks (no supports; just held down with a few rocks), and will minimize early bug and bird problems. One reason I have decided not to shade-grow even the small number of CT Shade plants that are among my varieties for this season is the headache guy lines present for mowing. You can also sew very effective bud bags (~24"w x 30"h) out of the spun 15% shade cloth.
I had many of my plants blow down (twice in fact, last summer) in sudden 50 mph wind storms, in late June, if I recall. I shudder to think what that kind of wind would do to a thin tent the size of a mainsail. The CT shade cloth (40%, I think) is a heavy, woven cloth, which accounts to some extent for the heavy wire John reports, plus the need to support gangly CT Shade plants. But it's also sturdier fabric, and much more porous to wind than a finely spun fabric.
If you do build the structure, and it does well, you may give me the courage to try some shade-grown in 2013.
Bob