Surprisingly the box-shape was the best. The low COG with the battery bay was better than the foamy fuse. The battery was too high up and it wobbled more because of it. So anyway, I crashed it. Going back to the box shape fuse. Easy to build, low COG, simple. The damage from the crashes has only been to the fuse, so I chop it off and glue on a new one. 20 minute repair.