i have the same issue right now... rockwool is currently being shipped...
if you cant purchase rockwool locally-- im taking it you probably wont be able to purchase anything else... like rapid rooters or oasis cubes..

I have read things about PH problems with rockwool and it might be a better idea to use the rapid rooters/oasis cubes... But i've already ordered my rockwool so... thats what im using and hopefully you can feel comfortable in using it too :-D

we should keep eachother updated on questions, it sounds like we are pretty tied as far as our grow set up and knowledge obtained...

hope that slightly helps! :thumbsup: