I would base it off of how you plan to sell. This map, I've looked at it in 3 categories...
Off-Booster: Any fast to farm in large amount drugs, I will never sell my expensive drugs off booster.
On a 2x or higher booster: If you're planning on waiting for a 2x, it's worth farming some of the bigger drugs (netherwart blocks, mushrooms - auto?, shatter wax, etc.).
On a booster with mules: These for me are some of the simpler formulas. For this, I would farm drugs like speedballs, weak/premium joints, and the simpler 2-3--drug formulas.