Scalp massage recommendations

Hi! I am a massage therapist and I'm interested in adding a scalp massage treatment to my services. I absolutely love doing scalp and face massages so I figured I could add it to my services. I want to enhance it by adding an oil or some kind of product.

1. I'm wondering if I should give different options for the different kind of hair types and hair concerns. Any lines that carry that?

2. I'm wanting the product to not leave their hair super oily and greasy.

3. Is there any concern or anything I should know about hair or skin before adding this as a treatment?

Thanks so much for any help that can be provided!