I want to know the answer to the following question:
Mantras taught in the Saiva, Garuda, and Vaisnava tantra will be effective if applied by who?
All the background I'm provided with is that "The Guhyasiddhi of Padmavajra, a work associated with the Guhyasamaja tradition, prescribes acting as a Saiva guru and initiating members into Saiva Siddhanta scriptures and mandalas.". Is that enough to answer the question?