I think you'd be pushing your luck. That is a lot of weight spanning 4'. The pressure on the glass could be too much. From what I learned about fishtank stand design, there should be supports every 2 feet. So the centre blocks stay. Her design is simple and would work. Don't forget the styrofoam!
Nope...not at all...google the pressure tables for joists and span.....most DIY stands are vastly over engineered for no reason and excessive expense.