Pre colouring hair

[robynjanehill]

Hello all!
Very pleased to be able to chat with fellow hair artists

I’ve got a client coming in to go from porous level 10, (long hair) down to about a 6 or 5 level mahogany.
She has about 2 inches of natural regrowth level 6.

I was thinking to pre colour using 6 level copper-red but unsure as to procedure.
How to get to mahogany and what brand to use?
I work with L’Oréal Dia Richesse, Dia light and Permanent: Inoa

Any ideas on formulas??

Thanks so much xx