you cant as there are three separate profiles for the rubber, the top and bottom are different thickness's to each other and the two vertical side parts. They have to be seem welded or glued at the corners as well. It took us six months development and creation of a new jig to make the complete seal.
I've got one OG seal in grey. I didn't notice the thickness being different. The ones on eBay are £35 each ouch! If I could find a suitable profile on a roll even if they had to be fixed with trim tape it would surely be much cheaper.