while unable to actually answer your question as I'm not an experienced flash-photographer and don't have Canon equipment, I can tell you that I find a lot of inspiration and information by reading from this website, dedicated purely to flash-photography: www.strobist.com
What they produce there is stunning and often very artistic but they also cover the craft.
Some of their "DIY" (Do It Yourself) designs for snoots and lightboxes are both cheap and easy to reproduce, with great results.
For certain photography - mostly macro and portraits in controlled environments, I - the consummate Cheap-O - have bought several different cheap LED work lights and flashlight. It puts more pressure on me to control WB and they are rather rough around the edges, so to speak - but they are cheap and produce a heckuva lot of light that you can see continuously, so the guesswork of using 1/10000sec of flash is eliminated.