[Peter Matteson]

If those cross braces are welded it will be a nightmare to keep your frame true and parallel without very good solid fixturing and welding.

The X-brace also lends itself to allowing you to get bent out of shape and not box when, not if, you get hit from both sides at the same time or sandwiched against a wall. It's a novel idea but I would at least put smaller crossmembers all the way across to make it practical for how rough the games are.