The assumption of an evaluation is that it's easier to read than to write. Even an inexperienced writer can help another by reading their work with the advantage of distance, seeing what the author cannot, where it is dull, where it confusing, where it needs work.
At the close of each meeting, two members volunteer to submit material for review, and two reviewers are selected. Five days before the next meeting, the writers send their submissions to the whole group. Every participant is expected to read all submitted material, but only the reviewer need to prepare careful reviews.
At the meeting, the reviewer summarizes the material for the group, then gives a close and honest critique of its strengths and weaknesses. The writer may then ask questions of the reviewer and all participants discuss the submission and the evaluation.