Not sure who makes it but it is tough. Just butted the seams up loose like you said and it hasent moved an inch, it was the cutoffs from the jobsite, about 13ft left on a roll, i only needed 10ft so it worked out perfect, heavy to.
Board under the jackstand and we do all the tig work at our shop, its conveyorbelt that fedex uses, its tough. Maybe some mig welding though, well put down something.