aboc C4P receipe
This is a 4:1 mix of Staminade powder and Ion Exchange Whey Protein Isolate. Staminade powder is available from supermarkets, and Balance Muscle Technology make an ion exchange whey protein isolate that's affordable, and is available from most health stores and bodybuilding stores.One cheap supplier is CityHealth, quick link
Mix it by weight, using your kitchen scales, and keep the mixed powder dry and cool, and only mix it with water on the day you will use it, and keep mixed c4p refrigerated, or it'll go off and make you sick.
We use Staminade power specifically because it is the only readily available sports drink that contains mostly glucose and some magnesium.
An article discussing the use of protein for endurance athletes is online here