@shortnWide good question.
I am experimenting with pot size this round and downsizing based off of the results I've seen JackMayOffer achieve on InstaGram. He grows 10' plants in 3 gal
smart pots irrigating with low volume/high frequency feedings, his plants are stellar and the buds are ANYTHING but small!
More root = More fruit is only relevant in Organic Gardening where a sizable Rhizosphere is needed to break down and uptake Organic fertilizer.
This round I downsized into plastic pots, fabric is much more ideal. Plastic pots will become root bound faster and need a drastic increase in PPMs to satisfy the root system, I am at week 3 and feeding, consistently, 1400 PPM.
Some of the information in here is false and does not apply to pure coco, a medium that is used in Commercial Ag to INCREASE drainage.
First, coco being an accelerated medium does not fall under the category of "feed your soil" because it is NOT soil, you do not pH it like soil and you certainly do not feed it like soil. Treat Coco the same you would in a hydroponic environment but slightly increase your Calcium and Magnesium. Once the Coco is 'charged' with Ca you will see growth that greatly exceeds any soil medium.
Second, someone mentioned soggy coco, that can easily be avoided with properly timed irrigation and with frequent waterings your root zone will receive more oxygen then you would by letting it dry out. Not to mention, you're not suppose to let pure coco dry out, it will completely throw off the nutrient ratios. For example, in my 3 gal plastic pots (2.6 liquid gallons) I run the 2GPH emitter for 3 minutes on 1 hour off. My plants stay moist but not wet, this is fine in coco because it is much more difficult to over-water.
Third, if you are interested in slowing your growth to that of soil then incorporate the organic fertilizers, like worm castings. Worm castings have no business in a hydroponic environment where your soul intention is to increase growth and production. I know in Commercial Ag small ratios of Peat are added to Coco mixes but I'm still not convinced. Peat drains slower, will compact and leave a crusty layer and it retains 20 times it weight in water. Only benefit I see Peat bringing to the table is it's ability to harbor Beneficial Bacteria.
Fourth, perlite. Perlite is only necessary when working with a larger pot then is actually necessary AND if you hand water or completely saturate your plant with each feeding. Why add a product to increase drainage when you can simply decrease your pot size and cost and have your plants dry quicker?
Lastly, if you can size your pot correctly and feed correctly you can fill your canopy just before they get root bound, then once root bound your plants will show flowers SUBSTANTIALLY faster and your vertical stretch will completely stop. This round I saw marble sized buds in 7 days.