what medium and container to use during Veg?

In small closet A, I have clones in rockwool plugs in dome propogation tray under flourescent lites. 18/6 on/off
In other small closet B, next door, I have HPS 400 watt (using growrocks). Plants are now in Growth cycle 12/12 in 4 Easy to grow autopots w/reservoir.

What medium - what size container - what closet should I put clones when they're ready to Veg? I can't use grow rocks for them because I'd have to water them many times a day, or so I've been told. I can't use soil because I'm going to transfer them to grow rocks in closet B when they go into flowering. I can't put them in with the plants currently in flowering cycle. Please advise - I'm new at this and learning as I go -Thanks

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