All that weight on 4 points?
I fear them. put a couple 30s on that stand thats 60g on 4 sq inches.. Thats quite a bit of point-loading on a floor. if your floor is cement thats fine, but when you are looking at wood over floor joists... I am not so sure.
lets see 500+ lbs of water / 4 posts thats over 125 lbs on a square inch of wood. I dont like those odds.
Someone tried to git ma a dual metal stand for 55g tanks just yesterday. I turned him down. thats over 920 lbs on 6 points.
I would much rather distribute that weight. not concentrate it.