I did some more research and found this - although it's not so relevant as it's more about secular rituals for the new year, I hope it'll be of interest!http://www.tibetinfor.com/tibetzt-en/festival/fes01/fes_01_09.htm
Starting on the 23rd day of the 12th month, people prepare for the most important festival of the year. Man will purchase dresses, cloth, sugar, barley beer, rice, flour, tea etc.. Woman will make `tsamba', butter, cakes, and will fry foods, wash head, plait braids.
On the 29th or 30th, herdsman will use flour to paint the `eight auspicious emblems' and use plasters to draw the reversed `swastika' for good luck. The monasteries will spread foods for the hungry ghosts and chase away demons.
On the new year's eve, the residence will be cleaned and milk curd will be mixed with barley flour to make curd-pastry. The whole family will gather together to enjoy the `rice soup with nine treasures'.
The Festival of Banishing Evils falls on December 29 on the Tibetan calendar. Similar expressions are found in ethnic celebrations around the world with a theme of driving away evil spirits. On that day, a sorcerer's dance is performed in monasteries and a general cleaning is done in every household to get rid of misfortune and pray for godly blessings. Every family will have a traditional New Year's Eve dinner of Guthuk and torches are lit and howling are heard everywhere in a collective prayer for a new year free from misfortunes.
On New Year's Eve, the family gets together and eats a kind of bread called dguthug, made of nine ingredients, including dried meat, butter bits, and the fruit of Manikara zapota. Inside the dguthug is a bit of wool or charcoal or some peas, pepper, or other objects. If one finds wool in his dguthug, he is said to be kindhearted. If he comes upon a piece of charcoal, he is blackhearted.
When the dinner is over, the family members drive away ghosts by sweeping all the corners of the house, rubbing their bodies with zanba, and then running outside to cast aside the zanba tainted with bad luck and disasters at distant road crossings or in the wilderness. As night falls, bonfires are lit everywhere. The adults hurry back home for fear of being chased by ghosts, and the youngsters shout and jump for joy around the fire.Preparation of Losar Eve
Preparation begins a month in advance. There is a general housecleaning, and auspicious signs are drawn with white powder in the courtyards and on the kitchen walls. Every family sprouts qingke barley seeds in water and puts the seedlings before the family shrine on New Year's Day as a prayer for an abundant harvest.
Another part of the preparation is the fashioning of a sheep's head out of colored butter. In the Tibetan language, "sheep's head" and "the beginning of a year" sound the same, and the sheep has traditionally been regarded as an auspicious animal in Tibet. A phyemar, or five-grain bucket, is a must. The bucket is vertically divided in to two halves by a wooden board and filled with zanba (roasted qingke barley flour with butter) and barley seeds and decorated with barley ears and colored butter.