great setup! start out the nutes at .5 to 1 ml per litre, plain water only til they get the first serrated leaves. Once they get a good set of three blade leaves increase to 2 ml per litre til they get a little bigger, then go up to three then four. All that will happen fast, in that small of a space you probably wont need a veg period, its likely you can go 12/12 from seed. I've been using those nutes for three years now with tap water only, never used RO so I'm no help there, I haven't measured the ppm since I first started with them, my ph was 8, the plants were fine even at 8 so I tossed the meters and never looked back. I use equal parts of the three each time no matter the stage but others back off the grow in flower. Get big bud if you can, it's a must have by most opinions. Good luck man!