Ok so for all drugs (except for meth and moonshine) the basic process gets %100 of the total drug value if you double process you will recieve 125% of the drugs value, you can do basic processes at black markets, but the black market will take a cut of your materials. Then yheres cartels, if you dont hold them you have to pay a 15% tax on all drugs sold (except frog drugs).
Tbh the events have gotten way easyer since ive joined olympus, i would encourage many smaller to medium gangs to do said heists, you can easily 5 man the bank.