Just to update - I picked up the MDF today and looked at some of the thinner wood. Yeah, not worth it - the hardboard is so flimsy at large size, my son and I actually lol'd when we pulled out a 4'x8' slab of it watched it wobble all over the place. So, yeah 3/4" MDF all the way around. Even the monitor bezel. This thing is going to be a dang 100lb plus tank without anything in it. And like 120lbs with everything in it. But that's kind of cool, so... all good.