Similar to this request that is already closed and can't be voted on - https://feedback.getweave.com/forums/310747-desktop-app/suggestions/43602021-save-the-date-reminders-send-too-early-in-am

We just had enabled save the date reminder SMS, and had multiple new patients who scheduled an appointment on Saturday and received reminders at 6:30am on Sunday morning.

This feature is basically unusable until similar functionality around earliest send-time is added like you have on regular SMS.