the first time i was going to go gray, several years ago, i started with the shade lighter technique. my original hair, before gray, was darkest brown, some people called it black. each time i got the roots touched up, she went a shade lighter. after a few times i hated the look and went back to coloring.
almost two years ago i decided to bite the bullet and just go cold turkey. i thought i might do lowlights somewhere along, but then decided not to color in any way as then i'd have fading, touchups, etc., everything i wanted to avoid.
i am happy i did the cold turkey way. for you, with a medium brown, it won't be as bad as mine was. and, i don't know what percentage of gray you have. if it is more of a salt & pepper, the grow in won't be terrible.
i used headbands to pull back my hair. at the very first it covered the roots, then i let the white show around my face, the back was black. for some very strange reason i got tons of compliments on it -- the whole weird look i mean! of course, i also got a surprising amount of friends and strangers voluntarily coming over and saying how great the white/gray looked against my face.
all in all, it's not as bad as it seems, tho i will admit there were tough days.
in the end, i am very happy i did it and very happy i did not bother with any color at all.