Help? Wait "Until" step is limited... need to schedule email trigger
Hi, I'm using an Event Program that is integrated with a webinar... and I have a trigger set up to send a "reminder" email to go out before the webinar starts, which would include the unique link for the user to join the webinar.
The PROBLEM is... I want it to go out 15 mins BEFORE the webinar starts... and in the marketo Wait flow step, the only option is to wait until the start of each consecutive hour, i.e. 9am, 10am, etc... (see screenshot)

My webinar starts at 10am and I want the reminder email to go out at 9:45am- But there is no option for me to select an "odd" time like that.
I CAN'T do a "batch" email program (schedule an email) because batch email programs lose the UNIQUE webinar integration which I need for each person to get their UNIQUE webinar link to join the webinar.
Any suggestions on what I could do? Thanks!