When are they ready for DWC?

I'm starting them in soil and moving them to DWC but I not sure when. What is an indication? What length should the roots and canopy be?

You could transplant at any time. IMO better sooner than later, much easier to deal with shorter roots. Also harder to clean the soil from the roots without damaging them once they have all tangled together.

i start mine in the 1 " rockwool then cut a 4 "cube down to the shape and size of my 70mm net pots, when roots are through both cubes ( still in prop usually about 1 1/2 weeks in) i pop into bubbler...... make sure to use cube caps to stop algae,, mine r doing fine this way, first time in bubbles mind u,gd luck buddy

dwc tubs are excellent at any stage from seed to clone. just give the roots a good wash and they could go in today with great results.

Thanks gents. helpful as always