I recently started buying the little 100ml bottles of stihl HP. They're slightly more expensive than the big bottle, but it means I can trust someone else to mix fuel if I happen to be up a tree. All my fuel cans are 5L (or 5 quarts for you statesiders). I usually have two cans mixed at a time, and find that will get me through most days. I have a larger 10L can clearly marked and in a different color which has straight fuel, but I very rarely fill it. It's only for big days. Not that many days I can get through 10L of fuel!
The other thing thats been bugging me lately, the last 2 times I bought the 1L bottles of premix, something weird happened with the lids. They just wouldnt seal properly, so if they tipped over they leak, and when you 'squeeze' them to get the oil up into the measuring bit, air was leaking out both lids no matter how tight you do them up so that you couldnt easily fill the measuring bit. Looked at the lids real careful, tried swapping them etc... pretty annoying. They never used to do that. You do them up, and they get to a certain point (which isnt tight enough), then they jump the thread.
I think I'll trial the little 100ml ones for a while, see how it goes. Would be nicer if they were blue though.
Shaun