I did a henna root touchup "cheat" and am so happy with results. I did a full henna already this month but because of my growth it doesn't take long before gray is all out there again. I didn't feel like having to do all that mixing and leave henna is for 3 hours like usual. Since 95 percent my gray is in the top front I took my Surya henna (chocolate) and applied it like I would a relaxer by dividing the hair in small sections and smoothing it through with a chemical brush. For the record, i ignored the product directions. I didn't shampoo first. All i had in my hair was conditioner and oil. If i had some gel or styler in I would have. The directions say don't use with conditioner but the ones I use are pretty natural so whatev. So after appling the surya I twisted that section and clipped it. Covered with plastic bag and cleaned my house for an hour. After I did several cowashes to rinse out dye to only that section, i applied li, oil, styler. The color looks great and it was super easy. Didn't even need gloves. Surya is kind of pricey but just using a little for touchups between full henna is very economical because I only need a little.
Transition your mind before you transition your hair.