The simple answer is it will work if your an experienced welder. Not liking the top support where the center 33g will be placed but again 2"x2" tubing should be sufficient if welded properly. I would also cushion tanks with Styrofoam sheets and not allow to sit directly on steel. There maybe slight imperfections not noticeable but will count for when tanks are full with water weight that styro will absorb.
...Ralph