This tarp would definitely need to be a cad design and each piece would have to be sewn together to copy the tarp.
This tart would be even easier to do one piece.
The only thing you wouldn't have is straight sides. The front would have less width due to the back end being higher.
The tarp under my name, (on the side), is the same design only I sleep width wise.
This allows me to sit up in the center where there is more room.
If you went with 2 tarps with the same square footage, 1 sleeping length wise and the other width, the tarp you sleep width wise will always be lighter.
It is also sturdier with a better footprint and again, more room in the center
The one positive for the length wise tarp is that you don't have the tarp so close to your head when laying down.
Another thing to remember is that with this style tarp to be off of the ground, you will have 4 separate ridge-lines that will all need to be guyed out with lines (all 6 of them).
This makes it so that you sometimes have to search around for a spot that the guy-lines can reach out to.
Good luck with your project.