I've got an 8x3x2 400g and 8x30x24 320g.
My next built will definitely be 10',12' long at least 4' wide and between 30-36" tall. No sand and properly planned flow will minimize the work on the bottom.
Side note I would really recommend a closed loop system for flow. Either a couple drain ports closer to the top and pvc returns down towards the bottom with vca nozzles, or multiple ports on the back with both drains and returns and vca nozzles! Lessens the need for a ton of powerheads. I run 4 jebao mcd10000 on mine. Never need to vacuum the bottom.
