Hi James,
I guess if my dog can chase ice chucks in my local stream, I can try to dive in to answer your question on what is turning into a beautiful Saturday
Emma just made a post before me. She has given some alternatives by spliting your courses and using the course completion settings, which I have not used.
When I was checking "watermark stretching" in another thread, I created 12 in one course. While you can edit the language strings and change "Certificate of Achievement" to "User Training Certificate" that will be a site wide change and not take care of "Administrative Training Certificate".
Approaching it from a different angle, you can make as many custom worded certificates as you want. You will need one or two custom ones. Check MoodleDocs for adding new custom certificates here.
Perhaps you have 10 different courses with different modules, but always with a User or Admin level of certification. In that case I would create two new certificate types, use the custom text field which can be changed in the certificate settings to say the "has completed User Training Modules 1 to Module 12" in one course and "has completed User Training Units A through Z" in another.
Or you could make a new generic certificate where the custom string and a few other standard text strings positions are always the same. But then have something like a custom border with the appropriate words as part of the image (your user, admin, trainer, yoda, maven or what ever certificate level). Then the teacher can pick the right image, add the custom text without bothering you for yet another "custom certificate". Images are easier to load than creating custom certificates.
Hope this helps. And thanks Emma for jumping in! Time for me to take my dog for a walk and check out the stream.
Chris