creating a neutral/cool red over bleached hair

I really want to stop bleaching my hair as I want to grow it. At the moment I have about an inch of my natural light ash brown root with a few greys the rest is a mix of straw and ash blonde. I want to henna it but do not want to end up highlighter orange! I know the bleached portion will be brighter than roots but figure this will look like ombre as it grows and I continue to do the roots. So could you recommend a way of getting a red rather than orange result. I want to steer clear of indigo as my hair grabs black and I don't want to end up with black/brown hair or risk the bleached bits going green. Would Amla reduce orangeness? My skin tone is cool so I look really sallow with orange I best suit berry red colours but a true red would be fine too. Can anyone offer any advice? Thanks x