What's the best approach to send email to users with an upcoming renewal?

Hi,

We would like to send an email and push notifications to users which are on our yearly plan and have an upcoming renewal in 7 days. We would like to avoid users who have opted-out for renewal and/or are on a monthly plan. 

I was thinking of the approach below, but I’m wondering if it’s the best way to do it:

• Use webhooks from RevenueCat
• When we receive RENEWAL or INITIATE_PURCHASE (with period=NORMAL to avoid free trial users), we schedule the sending of email/notification based on the parameter expiration_at_ms
• If we receive CANCELLATION with reason = UNSUBSCRIBE, we cancel the schedule for this user => not sure if we will receive this when the user opt-out for renewal or at the end of the subscription period

What do you think of this? Is there a better approach?

Thanks!