Last hurdle with my 120 site aeroponic unit.

I want to make a 120 site aeroponic unit. I want to make it out of PVC pipe and was not sure if I should go with 6 inch or 4 inch. I know 8 inch is over kill cause I'm growing in a 4 inch post now. My question I guess is Should I run the sprayers like I do now. ( like stink setup through the pipe. Or would it be easier to run it from the top? And how would I attached the spaghetti line to the sprayer? This is the only problem that I have come across. Everything else I have figured out.

Much thanks in advanced. . . .