You can also try the Dataform module. While it doesn't yet support the Moodle rubrics (prepared but not completed yet), it allows you to create a rubric as part of the submission form. That is, you can add grading and feedback fields, organize them in the entry template as desired with descriptions and styles (via a WYSIWYG editor), and then set the activity grading calculation you wish to apply.
The presentation at https://moodle.org/mod/forum/discuss.php?d=276190#p1187089 illustrates how grading is done (it would be similar for group and individual submissions).
The thread at https://moodle.org/mod/forum/discuss.php?d=276623 offers further clarifications how to construct the calculated grade in the activity.
hth
EDIT: Unfortunately some of these features are available from 2.7 onward, so may not applicable in your current Moodle.