The LOTR series had very low multiples, declining for each instalment from 2.59 to 2.37 to 2.10. The math, per BOM, is 47.2/18.2, 62.0/26.2, and 72.6/34.5.
King Kong had a massive 5.14. The math there was 50.13/9.76.
The above four movies opened about a week before Christmas, so similar to ANCH2. Though obviously different movies, the huge difference between all three LOTR vs. King Kong (also a genre film and with the same director) may make King Kong's 5.14 multiple more relevant than one might think when it comes to ANCH2. The explanation might be that, unless it's a massively front-loaded must see event picture like the LOTRs, people will wait for the weekend even if it's a prominent genre flick like King Kong.
The two Fockers sequels opened the Wednesday just before Christmas on Saturday. While that skews the comparison with ANCH2, it cuts both ways to some extent with the Friday (Christmas Eve) depressed. FWIW, the multiples there increased from 3.81 for the first sequel and 4.28 for the second sequel. The math is 46.1/12.1 and 30.8/7.2 respectively. Averaging those out might suggest a multiple of 4.045 would be possible, so perhaps 33M for Fri-Sun? (8.1 x 4.045 = 32.76).