I haven't read the entire thread so this may be repetitive.

I had some individual packets of Scratch powder. They might have been samples I picked up somewhere. I like Scratch because it isn't overly sweet, goes down easy and has good stuff in it.

Another idea: premix some concentrate in a gel flask, whatever amount of powder is necessary for your water bottle size and mix with water in the little flask. It will be easy to dump into your water bottle, top off with water and Bob's yer Uncle. Easy to carry in your back pocket and pretty much mess-proof.