You could do lowlights on just the gray root area to blend it in. This would let some gray show but also let it grow in together. From RC's website:
For hair that has lost dimension or needs to be a little darker. Follow instructions for highlighting with a cap. Use one of the Color by Robert Craig shades that is darker than the color of your hair now. Also, we have the Color Tool Kit that contains everything above except the bleach and it is available in the shopping cart under the accessories.Photo 18Photo 19
Following the pattern in these photos pull more hair out from the back and lower sides and progressively less towards the front. Photo 20Photo 21Photo 22
Formula 1: Grey Reduction For: Black or Brown hair with any amount of grey. Results: This formula evens out grey patches or reduces the amount of grey. Great for those who want to go natural slowly or don't mind some grey. This method allows you to go longer in between touch-ups because you aren't covering 100% of the grey.
With a highlighting cap, pull fine sections of hair through the cap doing more in the back and progressively less toward the front and around the face. If you have a grey streak or patch you can pull more hair from that area to even out the grey. Apply any shade of Color by Robert Craig that matches your natural, dark color on the hair pulled through the cap and process for 20 to 35 minutes. Shampoo, rinse and condition. Style as desired.
But I would choose a color 2-3 shades lighter than your base color, as most colors go darker on curly hair.
I think I'll be doing this when I'm ready to go gray, but that won't be for a while or until my gray comes in more evenly.
SF Bay Area, CA * "The Angel-Goddess-Guru of Haircoloring" 3b/c/a mix. medium texture, low porosity
My Motto: Strand Test! some hair pics
-- gone, but never forgotten.