You could try Advanced Nutrition Big Bud if you're determined to buy something to help. Only way to know for sure if it works for you would be to grow two clones one with it one without. Another angle to go would be to ensure your plants get plenty of Phosphorous and Potassium. Maxibloom is a good fertilizer with the nutes for flowers + has calmag and trace nutes. You can use both an NPK fertilizer designed to feed the plant plus big bud, big bud doesn't have any plant food in it.
Genetics are also a big deal as the other person mentioned. And two seeds even from the same pack won't have the same yields. IMO never grow white label seeds (free seeds with order, Seedsman, ILGM, etc). Always get your genetics from a breeder that puts their name on the line and spends a lot of time developing their strains and phenos. The - you pay for the seed will pay you back come harvest.