I'm afraid I don't have numbers for you because I never use that kind of hair dye.
What I do know that works well is bleaching your hair to a pale ginger or yellow, which isn't too damaging. That's assuming your hair is darker than blonde, if it's not then you don't really need to bleach more than a few minutes as you just need to roughen up the cuticle on the hair to give the next stage something to stick to.
From there, I'd use this dye which is exactly the right colour. https://www.beeunique.co.uk/hair-dye/adore-hair-dye/adore-ginger
This is a much better option than using a permanent dye because the Adore dye is completely non-damaging. Ginger dyes fade and look dull FAST, especially permanent ones (which I know sounds weird, but it's true). By using this kind of dye you can add some to your conditioner for a mini top up every single time you wash your hair. You can also dye it as often as you want. When your roots show, just bleach ONLY your roots and use the Adore dye again. Trust me, it's a lot less damaging this way 🙂
Thank you so much Janineb !i will try it.