See: Winterization
8-12 min “soak” without flow or agitation is almost certainly leaving a lot of the goods behind.
How do you get your solvent off the biomass? Is there a centrifuge involved? How much solvent (tincture with cannabinoids!) are you leaving behind? (I suggest weighing your bags post extraction).
I agree with @Akoyeh that paying someone to get you up to speed might be a good move…
investing in In House analytics early rather than late is also a pro move.
Have you got any analytics back on your current process? What is your extraction efficiency? (Follow the cannabinoids. How much did you start with. Where are they when you’re done?!?)