If you want to be able to enter E, M, N, Y, and U as grades rather than numerical values, you just need to use the grade mapping feature in Sapphire. This can be found under the 'options' drop down menu.
That's it! Not as complicated as it seemed :) I also set up the progress reports so that these weights, descriptions, and grade mapping print out so that students and parents can come to understand what it means to earn an E vs an M as a grade. I'll address that in a later post.