As far as the clay pebbles go. I started out using hydroton and I do like it.
It is a pain to clean the first time. But I have been using it over and over again for years now.
I will absorb water and it will sink to the bottom of the bucket of water when cleaning.
The last bag I got was of some gray clay pebbles from England and they don't absorb water and they float.
That makes them a lot easier to clean. Other then that they both work fine to support the plant.
I use Botanicare Kind and at one time used GH 3part I also ran Advanced for a while but I did not care for that one much it took to many additives for me.
With GH you most likely will also need some Cal-mag. With Botanicare Kind you should be able to do the whole grow with just that.
With all three you will most likely need to also have something in the mix to protect the roots.
I use z7 water treatment for that. Not sure you can get that where you live. But hydrogrard or a few other things could also help in the regard