You can water/feed coco-coir like soil but you will get soil results.
Think of coco-coir as hydroponics, as it is just a form of hydroponics.
You will see the best results with dairy feedings with a nice little bit of runoff.
You can get even better results if fed multiple times a day…
Search YouTube for “high frequency fertigation in coco-coir” and it will all make sense…
I’m of the mindset that if autos are not flowering fast then you’re doing good.
If they flower fast then potentially something is not right.
You can give them 48hrs dark but it want matter if you go back to a regular light schedule.
If you want to try snd induce flower then go to 12/12 and stay at 12/12.
Definitely crank that light full blast and feed at least once a day making sure you get a decent bit of runoff each time and you’ll be happy with the results.
Im betting with 3-4 days of this, you will see an explosion of growth 
That’s the last journal I posted to regularly, and heres what i have going now in coco-coir.
