I meant to ask you to take the chair and tell us how you would handle your parish’s Mass schedule this year that Christmas falls on a Saturday. I know some parishes have as many as two well-attended Saturday nights. What are you going to do on the evening of December 25th this year? Cancel? Do the usual 
confessions-plus-Mass? Or will the Christmas festivity “outrank” the Holy Family Vigil?
On a related front, we’ve landed five weddings in the last two years on or near New Year’s Eve. I played a wedding on New Year’s Day last year, and I have two on the Eve this year. Would you believe one of the brides requested I play her favorite Christmas song, “Go Tell It On The Mountain” for the end?
Well, given that on the evening of Christmas, vespers will be the second Vespers of Christmas, the propers for Mass should be those of Christmas. I realize the USSB staff has in the past favored the idea that Sunday propers always begin at sundown on Saturday and ignored the implications of the table of precedence for the calendar in this regard, hence confusion, though most parishes avoid the issue entirely by not scheduling Mass for Saturday evening.
It seems, however, that the USCCB staff has recently changed its interpretation and come to favor the more common canonical interpretation that Christmas trumps Holy Family on a Saturday evening:
http://www.pittsburghcatholic.org/newsarticles_more.php?id=2925
The preceptual obligation is not at issue here, btw; preceptual obligations to assist at Mass and propers need not be aligned.
(Btw, on the following weekend, Epiphany outranks MMoG in the table of precedence, so vespers II and the Mass propers are for Epiphany on the evening of 1/1.)
Yes, our diocese has the same policy.