You should post your students' marks as your course proceeds, when they become available. This is not a function of the grading programs, but they can help, and other facilities exist to work with the grading programs for mark posting.
The students' privacy should be a consideration, and the grading programs make some contribution by allowing you to omit student names (by using ghidenames) and to select individual students' data with the selection options. That's not enough, however, and you need to rely on some other mechanism to provide better support for privacy.
Security of your records is another issue. Some posting mechanisms allow you to post entire grades files — and that's fine, as long as you're keeping another copy somewhere safe.
Post on the CDF secure web site
You can post an entire grades file, or more than one, on CDF's secure web site for instructors,
https://www.cdf.toronto.edu/instructors/
The site verifies that your file passes glint, and then allows students to access it through the secure web site for students,
https://www.cdf.toronto.edu/students/
Students have to log in with their CDF accounts to use this web site, and can only see their own marks. In fact, even you can't see what they see, though you do see a brief extract of your file at the time it is being posted, so that you can be sure it is the right one.
This site works, does not provoke puzzlement among students, and is our best solution.
Post it yourself
Unfortunately, if your students don't have CDF accounts — perhaps they're engineeers? or in your 199 course? — then you can't use the CDF secure web site, because they can't log in. In that case, you may want to post on your own web site.
If you'd like to post on CDF, you can modify the files available here:
~clarke/pub/markpostdir.tar
That location is at CS Lab, even though the files it contains are for use on CDF. Move it to CDF and unpackage it in some handy location, probably an empty directory:
tar -xf markpostdir.tar
There's a README file, and you need to read it. It explains how to use the script, and also discusses the weakness of the security it provides. Still, it's not the worst available approach.
Post on Blackboard
You can also post your marks on Blackboard. You will need to do some format conversions every time you post, but Blackboard provides roughly the same level of security as the CDF secure site. To find out more, please read Working with Blackboard.