I had the 72g set up once. All I was able to fit was a 20g tall. Sump was on a small stand in the rear right side of the stand. UV
mounted on the back wall.
I would consider removing the tacked in cross support piece from the stand. The horizontal one - front to rear. Drop the tank in and securely re-tack the support piece. Now, consider that once you get it against the wall and full of water - you can NEVER get the tank out again. Put it there and practice a few dry runs of maintenance things to make sure you got work space before you commit.
BTW, with the 20g tall I had, I could actually pour a bucket of water into it - and reach my habd to the bottom. If the 30g is taller with the same footprint, you won't be able to do that. Likely will NEVER be able to reach the bottom of the sump with your bare hand. Can always pump water into the sump from a bucket or can with a pump and hose though. HTH
Was I clear as mud?? Starting to wonder...