Hi Crystal,
Tapihritsa is wonderful! Yes, Guru Yoga is actually part of the A-tri Ngondro, and it a part of this course. In Tibetan, it’s called “Lamé Naljor.” It’s the fifth of the preliminaries (Lesson 6). Rinpoche often stresses the importance of this practice.
In the A-tri Dzogchen tradition of Ngrondro, we visualize Shenlha Ökar as the guru/lama. There are several other traditions/practices for guru yoga/lamé naljor that use other deities as the main object of visualization (Tapihritsa for example).
While you can practice any or many types of guru yoga that you receive teachings for, I would assume that it would be recommended to stick with a single version while accumulating 100000 for Ngondro. But other guru yoga practices you’ve learned may also supplement your practice, even while you’re still practicing Ngondro.
Best,
Nick