So far as Gayatri initiations are concerned, the tape is not required. You have the threads, chanted on by me and now I am enclosing herewith copies of Gayatri mantra, one for each of the seven disciples to be initiated. Hold a fire ceremony. Chant Gayatri mantra to them individually and let them hear and repeat. Then offer the threads on my behalf. The fire sacrifice should be performed as usual.