Well, I've cloned in rockwool plugs as well as peat moss pellets, and haven't had problems converting either to clay pellets or hydroton. I transplant into 4" net pots, and use flood and drain on them, which floods every 4 hrs for 15 minutes. When I do this I try to remove most of the rockwool or peat moss, because the roots don't get enough oxygen if I leave the rockwool/peatmoss on them. If I didn't have that set up, such as you don't, I would probably put them in the same container with hydroton and not remove the plugs for added water retention, and I would guess you would not have to water more than once a day for the first 2 or 3 weeks.

SN