My very dear one,
Thank you for your letter. I checked and according to my observation, you need to read the Vajra Cutter Sutra five times for success of the retreat.
The entire Kangyur needs to be read once by the Ganden Shartse monks. You can discuss with them whether they can do it and the cost, and if you are able to, you should sponsor the offerings of tea, money and bread for however many days it takes. So you have to discuss this with the monks, to see if you are able to sponsor it and cover the cost they are asking.
If you can’t afford it, then if they have other benefactors you can do it along with them. If you can’t completely sponsor it by yourself maybe there are other benefactors who need this also and you can join with them, then you make whatever offering you can—half or whatever you can do.
Make requests to the monks to dedicate and make strong prayers to pacify obstacles, for the retreat to be successful, for the retreat to become Dharma, and for Dharma to become the path to liberation and that becomes the path to enlightenment; for retreat to be most beneficial for every sentient being to achieve enlightenment as quickly as possible. So that method is for yourself to achieve enlightenment as quickly as possible for that.
You need to recite Gyetongpa [Prajnaparamita in 8,000 verses] five times. It comes out best if you read this.
You should also recite the Verses for the Eight Noble Auspicious Ones. This is what is normally recited every morning, especially when beginning retreat, for success, especially before starting any project
The Four Mandala Offerings to Chittamani Tara puja needs to be done by the Kopan nuns.
Please try these, for the retreat.
With much love and prayers ...