The only real advice i will give about the autopot is make sure your girls are big enough before turning the system on i would say 3 weeks minimum or 12 inch high just to make sure the roots are at the bottom and can wick the feed up.personally i dont think it makes any difference how much hydroton is in the bottom as long as your roots are established i will prove or disprove this next grow when i fill the pot half way with hydroton then the rest lighmix/perlite.also get a good airpump if you are going to use the airdome i was told between 100 and 200 ltrs per hour but i have mine on full blast at 324ltr per hour because we all know the more air the roots get the better your girls will grow and my girl is flying.