My very dear one,
I am sorry I only just now read your letter that you gave during the retreat, I am very sorry for the many eons of delay.
I checked and you can do 800,000 Samayavajra mantras. This can be some in retreat or just on weekends and in this way slowly finish the number. Of course, base this practice on the sadhana.
I am very happy that you discovered this and knew how to think, from your own side looking at the guru as Buddha, even though I am not Buddha from my own side, but you knew how to look at the guru as Buddha, so you are very lucky. This is the root of the path to enlightenment, the root of everything, the root of all success.
Please make your life most meaningful with the thought of bodhicitta.
With much love and prayers...