1 vertical in the center would be plenty in my opinion. Just so the front bar wouldn't bend slightly and potentially crack the tank.Will support a 75 gallon rimless tank. Width and depth match tank dimensions. Steel is 11 gauge one inch tube. Will put a wood panel on top of steel and between the wood and glass I will layer on some 1/2 inch thick neoprene foam material. The steel frame is level and I will put some spare puzzle mats underneath a rug beneath it all.
The center two struts (back) each have 3 holes drilled with equal spacing. Will be painted but before I put primer on any thoughts on whether front struts are necessary? Either just one in the center or two?