With coir, smaller pots work well. I keep small donor plants in 2 liter square pots, with conventional solid sides so that each feeding floods through. Water-only often, and less intense light regulate steady growth rate.
I hydrate the block, then fill pots, then flush a bit with more tap, then transplant into, then fertigate/flush with working solution. Low ppms is OK.
I think casual, non-obsessive treatment of coco coir is key to success.
With basic, simple DTW, worry only about air and light on foliage & blooms