If looking for leather cord that is screen accurate, you'll need to go with a 4-ply braid that's 6 mm in diameter. The MJ Trim stuff is actually a six ply and about 5 mm in diameter.
There's actually a member here that makes some dang good braid that I've seen in person. However, he's never offered it up that I know of. It's the best I've ever seen, but depending on what type of leather Steve uses...he may have a contender!
Thanks Steve for signing on as this is a big void here as someone else already mentioned. I'd be interested in seeing some pics of what you have to offer in those specific dimensions.
Just some FYI for everyone.