I use rapid ruders. They are pre soaked so you don't have to pre soak them they are a small composted bark cube that stands about 2 1/2 in high. I have a friend that uses RockW and has pretty good success, he pre soaks the cubes in 5.5 ph adjusted water for 24 hours, takes out of the water gently shakes, puts the clones in and puts in a trey with misted humidity dome. when the RW cubes start to dry out a little he will put a light layer of water on the bottom of the trey. With RW you can use the 1 in and then when roots start to show you can get the bigger cubes with the 1 in holes all ready in them so you don't have to pull the clone out of the one in just put the little cube into the larger.
I can go over my cloning technique if your interested in using the Rapid Ruders. The reason that I am using them is because they don't have to be pre soaked so I can just cut when I am ready, for instance the other night when I was ready and had time, my RW cubes weren't, but the Rapid Ruders were. I didn't start my clones strait in the dirt because I like to know when it is starting to root and you can tell threw the ruders.
Hope this helps some.
If you are going hydro I would think about using peatmoss pellots, or the RW cubes.
Adieu