Summon Unhappy Girl, or Rai-Mei if you don't have unhappy girl, and stall until you can perform gravekeeper's vassal and union attack combo. Set a Rai-Mei when you set an Enchanted Javelin to raise your LP to ensure Tea won't attack the unhappy girl while also thinning your deck. Summon BEUD when you can before the last turn and leave 1 monster slot open for vassal.
Example deck (No Union Attack)
Works similarly to the method above, except the finisher is Cu Chulainn. Use the Rai-Mei to thin out your deck and summon BEWD early in the duel. Since Cu Chulainn's damage is only going to be around 5000, make sure to destroy her solemn wishes as early as you can, otherwise just deal the 5000 damage and get her to deck out.
This deck has been 100% for me against Tea and it always gets a 8K score. It can be used with or without a skill. It's pretty self explanatory. The only reason half shut is in here is for the prismatic bonus. Also the ritual monster can be changed out for whatever you like. But considering she can get around 14000LP's, you should make sure it has a high ATK.
Im sure most of you already know but this deck works on quite a few other LD's with a little bit of tweaking.