Ruslan, (is that your name?)
Like Greg said, there is enough extra meat on the canopy as you receive it that you can safely cut off a corner to practice on.
But if you'd still like to get some scrap to practice on for now, I have a few leftover trimmings that you are welcome to have. I'm in San Diego. Send me an email (email, not PM) if you'd like to come by.
-Roee