He's a link to an example of what I'm talking about as far as colored reins go:
Also - you stated "She's never liked holding the reins too firmly coz she doesn't want to pull on the horses mouth" - teach her instead of opening her fingers to open (and close) her elbows. I like to use the example of holding their hands - does anyone enjoy holding "fish" hands - where the contact is so light it's like holding a slippery fish? Conversely someone who crunches your (hand) bones is also uncomfortable. So best to keep a steady "medium" contact, which she can do by opening and closing elbows for a nice steady contact.