Fairy has done the analysis. You only need to decide.
Fairy recommends
Canary to 10% behind a flag, then ramp as metrics hold.
Fairy recommends
Use the customer's most recently used payment method.
Fairy recommends
CRM wins for contact fields; Fairy wins for activity history.
Fairy recommends
Add the regression test before merging.
Fairy recommends
Backfill the full 90 days during off-peak hours.