Sounds like it should be your friend here asking. And then you can help him setup. Dont try to setup up a system that you dont know to start with, especially not to a friend or what sounds like comercial - too much risk for both of you; him: loss of profits and lots of cash spent.
You: lose a friend arguing why it didnt live up to his expectation. Youll end up hating eachother before this is over.
The best answer here to your question is indeed coco drain to waste - handwatered. But it means your friend will not be able to leave the grow for more than over night, normally. If he then wants to go further he can always try develop it.
It is the best answer not cause it is the most effective - its the most easily adaptable to all other circumstances of the grow; its basicly the best we could give you since we know nothing about the rest of your circumstances. And its just trays and pots, not so much investment.
You see:
Choosing medium depends on lighting and somewhat climate. Lighting is best determined by climate (or what environment would be easiest to create and maintain indoors), energy prices and skill level of the operator. Indoor environment depends on sealed or vented and investment and amps available and again energy prices. All this depends on size and if personal or comercial. Medium also goes with what nutes you wanna use. System goes with availability to be in the grow, and how much effort he can put in daily. Are you starting to see a picture? He should decide by making many questions and inquiries himself, then you can use your know how in how to setup. I dont doubt that you have good experience growing within your system but have you ever setup and designed another system yourself? Its not the same as growing the same organic flowers as youve always done.
And are you even sure you have maxed out your organic approach? If you had youd probably be trying to steer him towards organic soil with SIPs. But that could also go wrong if he changed lighting from HIDs to leds; i wouldnt rec any system with all nutes in pot by start of flower with leds. You will be needing a way to adjust over night.
The whole thing also depends on size of grow; some system are great but labor intensive: imagine having to mix up all that organic soil for 200 plants on your own? But if it was 4 its not a biggie. Have you considered his water source and how it comes into play in the system? We need to collect rainwater for our grow, no other way to do it in our conditions. Are you on well or city water? How much water could you reliably use per day?
Handwatered drain to waste coco means your buddy can start somewhere and its easy to find a solution to all these problems that can arise. Its close enough to being ideal, other systems will depend on so many things that we may inadvertently set you off to a system that simply doesnt work for his specific conditions.
His skill level is also a factor. Slow organic, where you dont push the plants as hard as in other cases, with HIDs is one of the easiest ways to grow. Going to another will immediately increase skill level requirements.
If he wants to flex on the poors growing in muddy cowshit.....I would suggest high pressure aeroponics. You need all sorts of fancy stuff like atomizers, solenoids, check valves, logic boards, micron filters, expensive pumps, manifolds and a lot of patience when all that stuff starts to malfunction.
No shade on aero but have they got enough to pull that off on the first try setting up?
