Seeds germinated in two days and had grown just the perfect sized root to be transplanted into small rockwool cubes.
I cut the rockwool cubes halfway and then carefully place the root inside the rockwool leaving the seed out. Then I place the rockwool cubes into small net pots that keep the rockwool cubes closed and also fit the final sized rockwool cubes.
I've also noticed using net pots helps preventing stem rot in my NFT systems because of the small air gap between the small and final sized rockwool cubes created by the net pot, so the small rockwool cube wont get saturated with water after being put into NFT.
I used to get stemrot back when I germinated my seeds in Jiffy coco pellets and placed those inside the round holes in rockwool cubes and then the Jiffys would get super wet and saturated and I feel like that was causing the stemrot. I dont think I've had the same problem when germinating the seeds in small rockwool cubes, now that I think about it.. Anyways, using a small net pot between the Jiffy coco pellet/small rockwool cube and the final sized rockwool cube seems to eliminate the problem too.
I also think seeds germinate/grow roots a lot faster in Jiffy coco pellets than in rockwool cubes.