I am going to say make it whichever day works best in your plans and strategies and go with that. I have found the
MVMCP to be packed no matter what day of the week it is. I personally don't think one day from the next really matters. These hard ticket events have become so popular that they are just about sold out or close to sold out regardless of the day. When we attended the MVMCP back in December 2013, it was suppose to be a lower attendance day at the MK, lower attendance forcasts for MVMCP, and in WDW as well in general; Instead it was very busy. In spite of all that we had a great time and would do it again.