If you really want to get into the weeds look at the SSC monthly reports for Jul Aug Sep of LAST year. Attachment 2 chart shows PPM and it drops off like a cliff in Sep meaning they don’t need to resort to premium flying because they haven’t run out of reserves meaning reserves aren’t maxed out. Attachment 6 shows hours flown per reserve and % of days used per reserve and both drop significantly in Sept.
OR just do what Cal73 suggests. If they are overstaffed the reserve pool will be positive and line holders get first crack at trip trading. You might be able to drop an entire trip or two outright. The last 10 days of Aug for DCA 737 FO currently shows 8 of those days significantly over coverage even though trip trading has been going on for over two weeks, showing the back to school effect.