Trinity:

Yes I know and my plan was to transplant into 3½ gallon pots, I already have them ready here but...
I am convinced I can do the transplant. It will be a stressfactor surelly but with lots of care taken combined with fast working and getting the ppm and pH levels exactly the same as they had in the coco to start with I would be surprised if they go hermi on my ass. If one or two does so be it and lesson will be learned from it. I have clones ready to go in that case. And this first grow is for one purpouse only. Learn as much as possible about MJ growing so I rather test the limits now than later.
I have spoken with two growers that both have done the same transplant, one from soil and one from coco by cleaning the roots and getting them into DWCs mid grow. Both got a few days growth stun but after that no problems. Natrually I will not push it if the first transplant turns out more problematic than I hoped but I will try on at least one. I don't stand or fall with these plants.

Pain:
Are that some sort of spungy things?
You see one factor with coco is buildup of salts and that's why you cant let coco dry out as the medium very fast builds up salts then. My concern with using stuff like that is that it might make this process faster. Flushing soil is normally no problems at all but flushing coco to get rid of salts or what have you drains the medium of all nutrients and the plants are left with nothing until levels are built up again. That is why coco is watered to a runoff of 10-20% at every watering. You water with nutes and to put it simple the first 20% of what you water flushes the salts out while keeping the nute level in the medium, the following 80% is what stays in the medium for the plants to feed off.
If you water slowly like these things sounds like they are doing you don't get that clensing I fear and might screw up the balance in the medium causing you to have to flush and then build up the balance again.
In coco you can not overwater and root rot is basically impossible to get but you can easilly underwater. Total oposite from soil where overwatering is always a risk but underwatering is generally not a risk to the plants.

Puffzter