I'd try for an earlier time. With your PS, you're assuming you will be seated promptly. And dinner is usually an hour or more. During the time that you will be eating, the first parade may start, Christmas stage shows will be running as will the rides.
We'll be doing
MVMCP this year. We originally had a 5:30PS at CP. We switched that to 4:20 so that we would be out in time to be herded into Tomorrowland. We plan on snacking later in the evening. With children 5 and 7, I don't know if they'll last the whole night, so I want the flexibility to pack as much into those first few hours as I possibly can.
Before children, we attended a few MVMCPs and were very casual about it. Sometimes we would not get into the park until 7:30-8. Other times we skipped watching the parade and did rides and shows.
I think your decision depends on what you want to get out of the evening.
