... and how to deal with and/or avoid them
Excellent discussion as always, David. This is something that I have struggled with as well. I especially like the idea of giving the grades meaning. This term I am thinking of creating that meaning with my students during a class session before midterm grades are due to give another opportunity to discuss the grading structure and make sure everyone understands. I am hoping this gives them a little more buy-in and understanding on what I am doing and what the "grade" means.
To your last point regarding the fancy commands using Excel. I have successfully used a mail merge to accomplish a similar task. I can get those emails sent out fairly quickly with a mail merge and I highly recommend it. I am aiming to send out these progress report emails roughly about quarterly. I primarily do this for transparency and to have the students check my work. Every semester I inevitably make errors inputting grades and I want to build lots of opportunities to find the errors.