actually these all have scientific basis for use according to the NSCA journals of strength and conditioning, but arginine has the weakest claim with BCAA's having the strongest.
1. Glutamine and creatine should be taken seperately.
2. Arginine should be taken before a workout. But can be taken afterwards, though it will not really be that effective if you are more concerned with taking it rather than getting your post workout shake and food in you.
3. Athletes begin to show dramatic signs of being able to maintain physical ability if they begin to drink bcaa's from the beggining of the workout to the end.
4. No supplement is better than a good diet.
5 Luecine in a study was shown to allow the body to increase muscle mass in secondary and no active muscle tissue in users = muscles other than the ones being trained seem to get stronger from BCAA supplementation during workouts (reason Muscle tech came out with luekic, to try adn capitilize on this info)
6. Glutamine is especially important during cutting because it is used by the immune system as well