I have come to know through Sudarshanam that women should not touch Salagrama deities, but Andavan Ashram has published a book on Tiruvaradhanam that can be performed by women which states that even the mantra to touch Perumal. I am confused about following the right practice.

Women do not perform Tiruvaradhanam as per the practice; only men are permitted to do so. When men are away, women can offer cooked food, clean the place altar, draw kolam, and offer flowers and light lamps as per the ordain. If there are books written on this subject one has to understand the actual context through relevant research. Rather than what is written, one has to follow what is in practice. We are following the traditional practices that had been in order. Women do not touch Salagrama deities as per the practice.