Yes, I tried your script before, and this works fine. And has much more options than I need.
I would like the "pure" functionality of ShiftOff. If I understood right, when ShiftOff is active, Shift + Key should work as usual, CapsLock should work as usual, but CapsLock + selected Key should be equivalent to Shift + Key. I did not succeed in modifying/reducing your script to ShiftOff functionality only.