I can't offer truest experience, GLC because I haven't gotten grey alot. Just a few grey strands among black hair.

You need to feel most comfortable. However for your job, it can't be a terrible thing to have some grey hair since personnel recruitment does require an experienced person ...and someone who looks fit/healthy helps enormously. If people already know that your former experience is engineering hands-on, an engineering degree PLUS other stuff, you would be a role model/mentor to others...particular for women in engineering positions. I worked in several organizations (public sector and large global firm), where licensed female engineers with demonstrated engineering experience, savvy plus defined LIFE experience do tend to be respected by their male engineering counterparts. Just a personal observation.

GLC, think of someone who is non-white, what they might have to do express themselves to counteract stereotyping of ie. not being born in North America, when they are. This is why if later I am judged by being older/ageism..... I can't worry about it much. Because I've judged negatively (based on comments to my face) in the past wrongly based on other visual cues.

But great that you have taken steps to "try out" greyness.