I have learned the hard way and would not book sit down dining during a special event. Part of the appeal and/or price tag is that attractions can be enjoyed with much lower wait times. In order to take advantage of that I wouldn’t spend an hour plus at a TS restaurant. I know that isn’t what you asked but it may be helpful.
Unless you are super set on a specific restaurant and are only going to Epcot during the AH event. Bear in mind that not all restaurants may be open during that event either. If the AH event allows you in at 7 and the park is still open until 9 you may want to consider dining during that window to give time for the regularly ticketed guests to exit the park and enjoy the rides after that.
To clarify, is the event specifically Epcot After Hours or is it something else?