The paper includes examples of Magic Kernel Sharp 3 (the original), 4, 5, and 6. The C code allows you to use any value 'a' of these "generations," and any version 'v' of the Sharp kernel listed in the paper (up to a = 6, v = 7), for any case you want to try. I may add more versions later.

The Sharp+ is just extra sharpening. It's included in the executable, but isn't fundamentally anything more than extra sharpening over what tries to be as-close-to-ideal resizing as possible.

Ahh, that would make sense; it didn’t occur to me to check the paper. I was mostly curious to see at a glance how it would visually compare with the addition of sharpening. Ultimately, it ends up looking pretty good.

Yes, and if you're comfortable pulling down the code and running 'make' on any *nix system, there is an executable 'resize_image' that lets you test it out for yourself. I'm always looking out for corner cases that stress-test the differences between the algorithms, so let me know if you find any good ones.