Have you ever looked into modifying your Canon OEM hood?
My 300f2.8 hood (before I dumped the 300f2.8 and opted for a 400f2.8 only in my long lens kit) was halved-in-size. I found no difference in flare with a hood of half the the length and the benefits were tremendous.
Before anyone asks how I tested for flare, I've covered international ski and snowboard events, ski jumping and other winter events. If flare is going to show up, it tends to show up A LOT shooting these events in the early morning and at mid-day. I've also shot with this kit covering a lot of other events under nearly every potential lighting situation.
The benefit of the 1/2-length hood is gained space when packing, increased mobility when shooting on a monopod when in a cramped situation (covering politics in a pack, covering sports in a packed photo pit), a 1/2 length hood also cuts down on the movement when you need to hand hold the lens in any wind situation (or not wind situation,it's just better balanced).
Just an idea to make your gear more effective.
......when I shot Nikon, and covered pro sports and other upper level sports for much of my living I had the 300f2.8,400f2.8 and 600f4 (well I had the 600f5.6 for a while then got the f4). My 300f2.8 had the flexible rubber coupling for a hood, then my Canon had this hood and a modified OEM hood. My 400f2.8 had a modified Nikkor hood (cut in 1/2) and the 600f4 hood was a one piece (since it was a manual focus) which I swapped for a new 'two-piece' hood and just never attached the second outer piece. I know using OEM gear is a 'status symbol' but once you start heavy traveling (and I fly 200,000+ miles a year for my work as a photog, having covered the Olympics, World Cup Soccer, Super Bowl, World Series, Stanley Cup, some international Cricket Match that put me to sleep twice in one match, etc etc etc) you'll start hating the weight. You'll start looking for options. Think outside the box and save space, weight and reduce your risk.
Crazy, I thought. Then I said, he's done this about 500 times in his 30 years working. I'm all paranoid.
