If you do end up doing a depp, you just flip them when they fill out the space. 100 in a 20x40 will probably only take a couple weeks to veg to fill out that space. If you don't want to depp it, you should wait. Plant in August. Or plant 40 of them in ljuly in 45gal pots.
Try cloning in oasis cubes. Seems to be the easiest medium to work with cloning.
It's different then everything else. Its florist foam. Clones won't wilt. U don't have to use domes if you don't want and they still stay perky. They don't get all yellow. You can cut them as big as you want and leave all the leaf on. They won't droop.