Interior battery box dimensions?

Finally received my 8– L16 batteries today, and installed under stairwell/solar room. Trying to get ideas on battery box dimensions. The actual footprint is 50"L,
16"W & 21" to top of cable arch. Will also be installing "The Power Vent"
8-420AH US Battery L-16s, Midnite Classic 150cc, Whiz Bang Jr, Magnum MS4448PAE inverter/charger,  4590w Canadian Solar panels. Honda EU2000i generator.