I've used Rapid Growth before, its OK, you can do better. A protein drink is just that, a protein drink. A weight gainer is protein plus carbs, which may be derived from simple sugars. You dont want that. I'd buy both a protein drink and a seperate carb drink. A heavy molecular carb drink. Mix them together. Under 20 grams of protein is not ideal. I'd go with something in the high twenties low thirtys depending on serving size. I recomend Fitness Central WPI 99 bucks for 3 kg, and then buy some carbs, Waizy Maze is ideal or Virtagro. Ive used Syn Tec before. You can add these in after workout and maybe before bed or on rising. I would prefer most of your protein and carbs came from food. After workout food isnt ideal, go 50/50 protein/carbs.
AZZA