Workshops enable you to set different due dates in order to submit work and assess other students' work. If you set both due dates as the same, many students may submit their work just before the submission deadline so that they cannot be assessed at all before the assessment deadline. Consider setting the submission deadline well before the assessment deadline. So, before opening up the assessment ability to students, examine the work submitted and ensure that it's close to what you expected or were trying to elicit from students. You may even want to use the time between submission and assessment to refine your assessment criteria, in response to the work submitted.