rock wool is fine.
you need to soak them in ph`d water overnight first. then i cover mine with dome and open a couple times a day to check and let in air. it`s hard to tell you how much to water as they are all different. dont keep them soacked but moist. warm temps, like around 78 to 80 and the higher the humidity the better.
also i like to gently scrape the outewr skin of the cutting about 1 inch up from the bottom, helps the roots come out.
i made an e-book on cloning using peat bpucks but i aam changing to rock wool myself on the next batch. i found that the peat pucks have to large a hole in them and dont stay in contact with the stem to well.
i have it in my other pc, if i can get it i will post a link for ya or something. good detail pics to of my plants and topping them.