Actually, Kaemon, MSE does
not work on Mac computers, while this program appears to work only on Macs. So I'm glad to see there's a Mac developer out there who can help the Mac community join in on custom card creation.
I would, however, like to correct some of your credits, since it appears you've sourced your images from the MSE template. While dok might not mind the credit, the images were created solely by Mooseman. dok did the scripting to make them work in MSE. The "purple card" blank was designed by Deliriant and created by myself.
Good luck
. Feel free to take more blanks from MSE, if you can use them, it's become quite a collection of standardized card blanks, and you can't get a lot of them anywhere else - just make sure you double-check the credits in the readme.
I wish I could try it out, but I've never used a Mac in my life.