There are many ways to configure assignments in GradeCraft. The best practice is to think about what your learning objectives are for the class and how to implement choice and student autonomy. You can even start out small - give students an option to resubmit assignments until they reach a certain grade threshold or give students a choice to complete 5 out of 10 possible tasks.
As the instructor, think about your time as well - you could give students an unlimited amount of time to complete assignments, but if you have a large class, you may want to find ways to chunk up submissions so grading does not become overwhelming.
Another best practice would be to create rubrics and quick grades that can provide more timely feedback to students while easing the grading burden on instructors and TAs.
For more information, please refer to this article about gameful course design, as well as our gameful pedagogy site. If you have further questions or concerns, feel free to email us at help@gradecraft.com