For creating a shift overview (how many workers are grouped in shift 1,2 3 etc), it would be nice if you implement a presence filter that shows, if the minimum number of workers for the shift is reached or not.
E.g. your project requires five workers for each shift. At some day, only two workers are scheduled for this day, so the adjusted filter (workers a day has to be minimum 5) shows a red mark (< 5). You fill up this specified day with the missing workers and it changes to green (> 5).