Trigger Action - Be able to set the occurring time to 30 minutes

We have our door code going out in an email to the guests at 2pm because the guests check in time is at 3pm. We are looking to make it at 2:30pm but we see that isn’t an option because they are set for every hour. We think that having it 30 minutes prior to their arrival would be a better feature. Even if there was a way to customize making it a time you preferred to have for the guests.

15 minutes would be better. 

[Another topic was closed as a duplicate of this topic (Delaying triggers by minutes or hours)]

15 minutes would be good...

I still have not figured out how to send same day booking check in messages with a lock code. It usually takes 5-10 minutes after the booking is confirmed for the lock code to set and I need the check in message to delay till then. Otherwise, the lock code provided may be incorrect. As of now, I have to send same day booking check in messages manually which is a pain in the butt. Any recommendations?