heres the deal...
most whey protein powders have very good amino acid profiles. the branched chain amino acids are included in them.
you dont need the bcaa's if you have whey protein in your system already. and you should be drinking some whey prior to your workouts anyway.
bcaa prior to workouts would be ineffective, well, better stated, they would be redundant.
its a good idea to take some bcaa's during your workout as they are primarily what gets degraded during your workout, and are also very potent pro-protein synthesis nutrients, especially at this time. you might try a small amount of that carb powder with the bcaa's in order to better send them into the muscle via the surge in insulin.
post workout is different...and largely depends on what youve eaten throughout the day leading up to your workout. if you have a large amount of available amino's, then all you will need to do is replenish your essential amino acids. so a bcaa/eaa product would work very well post workout. you dont necessarily need another whey protein shake, because your body can only use so much protein for tissue repair at one time. the pre-workout whey is quite diffierent because it is not meant to be used for tissue repair but instead as a source of energy and as a potent incourager of protein synthesis by way of its bcaa content. primarily the branched chain amino acid leucine. whats most important post workout is that you give your body ample nutrients to function without resorting to its protein stores for energy. that means you need carbs.... and if your not worried about some extra fat storage, plenty of carbs