I grew mine out about 8yrs ago, just got it cut fairly short and kept growing it until the nasty blonde I'd been dyeing it was gone. Never regretted not having to get hi-lights done or putting dye on it for one moment. After dealing with 'roots' most of my adult life it was a great relief to finally be 'done' with all that.
I've just discovered a wonderful product called Magic Touch by L'Oréal. You spray it in and it conceals grey roots, so may well work for you. It shampoos out, so is just temporary when you want to look your best while you are going grey gracefully.
I used a semi permanent on the roots and then had a shot fish cut. It took about a year in total but I'm so glad I did it. Mine is still quite dark at the back.
I started growing mine out in the autumn several years ago. I found a spray that blended in the grey temporarily to my dye colour. Then, when it was cold, I wore a hat to go out in the winter! By the spring, I could have a shorter haircut, which got rid of nearly all the brown....actually was a lot easier than I thought it would be. and I quite like my new grey too.
Try ash highlights on the dark bits or even white highlights. A good cut should reduce the tabby effect. I have documented my "journey to grey " last autumn It went, cut, highlights, ash toner, then white/platinum highlights to lift the remaining dyed hair and within 6 months I was there!! Now it is white with a grey bit at the back on the crown but I quite like the contrast!
Has anyone tried growing out their grey hair? I have tried several times but once it gets to a certain point I reach for the dye. My hairdresser has warned of this. My hair is all different shades right now, almost 100% grey on top, lots of dark at the nape with salt & pepper too