These drinks are calorie free, which technically should help people lose weight and prevent sugar-related diseases like metabolic syndrome and diabetes. However, the evidence for these beverages having any use is completely nonexistent.
The classic approach to performing supersets is to work two opposing muscle groups back to back without any rest between sets. This technique is usually applied to antagonistic muscle groups such as biceps and triceps, chest and back, quads and hamstrings. An example of a superset would be one set of biceps curls immediately followed by a set of triceps pushdowns.
You'll hit it hard using supersets and tri-sets with little rest in between, then train the rest of your body in the remaining 20 minutes. This will allow you to maintain size and strength everywhere else, as well as cause the release of muscle-building hormones that will enhance the results you see in your chest.