I have a large, multi-section course and we use barcode scanners to take attendance. We have built a program that can take all the scanned barcodes and create a Canvas Gradebook Upload CSV for us to import into the gradebook. This is a really quick and efficient solution for us.
In a single section course, this works like a charm because we can fill out the "Section" column with the one section of the course.
For cross-listed course, Canvas looks for something different. The section for some students is "Lecture A and Lab B" and "Lecture B and Lab D" and "Lecture A and Lab D". Can the section column be left blank as long as we have other identifying information for each student? Canvas appears to time out when we do that and we can never get anything to import.