There is no need for weight gainers, and I would not try the 4000 calorie diet as suggested, but I think that 2400 is quite low, and I who are your size would lose about 1/2 pound per week on this (indeed, have before). I kinda think 3000 is a better starting point based on BMR and need to have a calorie exess approaching 500 calories.
I weigh 150 pounds also, and know that I would lose weight on 2400 calories.
Check out the various calorie equations (e.g., Harris Benedict) and you will note a slightly calorie deficit at 2400 based on moderate exercise (e.g., 3 weights sessions per week).
Most people bulk on a 10-20% calorie surplus; hence, closer to 3000