The no-show was decided earlier than you think
It is tempting to treat a no-show as an event on the day, caused by forgetfulness and solvable with reminders. Reminders help a little. The larger factor is how the meeting was agreed. A meeting with a stated purpose, a stated duration, the right people invited and a date within a few days is a commitment. A demo next week, agreed at the end of a long call, is a placeholder.
This has a practical consequence: if you want fewer no-shows, spend your effort on the last ninety seconds of the booking conversation rather than on the reminder sequence.