I am in the same situation as you, and can offer some advice. I did 9 nights in early December in 2015 and will be returning for 12 nights this December. Last trip we did not have Park Hopper, this trip I will. Since you already have Park Hopper, I would suggest taking advantage of it. Your assumption is correct that EMH often results in larger crowds. It seems to draw in larger crowds on average, but the funny thing is that most people typically don't take advantage of those actual hours. My wife and I's favorite day in Disney was the day we dragged ourselves out of bed at 6:30am to do Rope Drop at Magic Kingdom on an 8am opening. It was 2 hours of practically non stop rides without lines. Once it hit around 10:30, the park started getting much more crowded, and we spent our time doing Fast Passes, Lunch, and lower demand rides. So our plan this trip is to avoid EMH Parks unless we are targeting those specific hours. We also plan to visit Magic Kingdom on
MVMCP nights to take advantage of the lower crowds, then bounce to a different park at night. If seeing the Electrical Parade and Wishes is something you are interested in doing, target Monday or Wednesday. Saturday at MK was a nightmare. If you want to see Illuminations, I suggest Tuesday to take advantage of Epcot's extra magic hours. That way you can stick around Epcot a little as a majority of the park is rushing to the buses/parking/monorail.
Remember, you don't have to plan every single aspect of your trip in the next week. You just need to plan your ADR's. So focus more on figuring out JUST the days you plan to make ADRs. Lets say you are thinking of booking BOG dinner, and you narrow it down to 2 possible nights. Just book it for both nights and cancel one when you get all the information that you need.
I looked at October and November's schedules to try and find a pattern with EMH's, and this is what I came up with...
Sunday - DHS Morning
Monday - AK Morning
Tuesday - Epcot Night
Wednesday - MK Night
Thursday - Epcot Morning
Friday - DHS Night
Saturday - AK Morning
The big changes from my 2015 trip is a lack of Osbourne Lights and AK being opened at night. They are currently showing DHS closing at 7pm. So its hard to say how these two changes are going to impact crowds. I dont think we will have a real idea until the Halloween Party starts as what to expect. If Magic Kingdom and DHS are closing most nights at 7pm, it will make things interesting for sure. Might also increase the demand for Park Hopper. The nice thing about Park Hopper is that crowd estimates arent as important. If you are in a park that has heavy crowds, just head somewhere else. The time you spend at a park with lower lines will more than make up for the travel time.
