Always neutralise what you're exposing.
Base 6 = orange, orange-yellow, yellow, pale yellow and very pale yellow.
So your formula would be 12/89
/8 = pearl (blue) to cancel out orange. /9 = cendre (soft violet ash) which will take out the pale yellow but i'd also add some special mix.
Base 8 = yellow, pale yellow and very pale yellow. Formula 12/61, /6 = violet to cancel yellows. If you wanted a different tone you could use 12/96 which is more pinky.