Agreed, we were thinking of doing week long rotations (Tuesday - Tuesday) with a "hand off conversation" happening on Tuesdays.
The reason for this discussion is because up until a certain seniority level, you get "hazard pay" for carrying the pager. You get paid 1 hour for every so many you're on call. A weekend/holiday is 24 hours instead of 8 on the day your receive it or 16 on a weekday.
You should also cover rules for holding the pager. Ours include no alcohol, and no more than 1 hour away from the site (certain emergencies may require on-site visits). You also need to respond within 20 minutes, otherwise it gets escalated, or in certain larger locations, sent to the backup on-call person.