NFT SOG Perpetual

Im in the process of building my first NFT system. Im using 4 pieces of 4in PVC to construct my tables. Debating on jamming 20 plants in each system or spread them out more and just put 16 on each. This is also my first attempt at the SOG method so all input will gladly be accepted. I plan on building 6 of these systems over time so i will have a perpetual grow. They will have a 1000w HPS over each and i will be vegging clones with T5s in a separate room. Im gonna use GenHydro nutrients because i already have some and it seems to get the job done. Ive used it twice before and i have no complaints.