I have now implemented 2-stage exams for all my courses (currently Analytical Chemistry 1 and 2, and Thermodynamics.
It’s been smooth sailing and the feedback from students has been very positive. They like that they know immediately, how they did on the individual exam and the fact that they can review the concepts with other students during the group stage.
There were a few issues to address during the implementation and apart from scheduling and training TAs, accommodating students writing with the Access Office for Students with Disabilities (ACSD) at Concordia has been the most important one. My priority is to have students writing the individual exam with ACSD write the group exam with the rest of the students together so that they can join the group they have been working with during the term. And support from ACSD has been great regarding scheduling individual start times so that all students are on time for the group stage at the common exam room. This has, so far, worked for midterms and finals!