What is the safest way to cover grey hair bwt. highlights at the hairdressers?

I will be 52 this week and find that I finally need more than just 'highlights' and lowlights via foils. I am thinking of all over color. For now, I was thinking of finding a temporary way to cover the streaks of grey coming in between the blond and dark blonde hairs! Any easy and safe for you and your hair ideas? I have been spraying my hair with 'Be Blonde' spray on color on the crown which washes out though when you shampoo...I'd like it to last a little longer than that...What is the safest way to cover grey hair bwt. highlights at the hairdressers?
Similar problem here. First of all, I stopped doing the lowlights a few years ago, after a new stylist told me it was a waste of money. I found out it was, and have only got highlights since then (still a bit angry at the first stylist!). I also considered all over color, because I would do it myself then (LOTS cheaper), but this is what stops me: with the highlights, the incoming grey is camouflaged for a while by the blonde (highlighted) color against the brown (natural) color. With all-over blonde, the grey and brown roots will be the only contrast and will probably be more noticeable right away, One thing you can try is doing all-over color and just touching up the roots pretty often, every 2 weeks or so depending on how bad you think they look. You can even do it yourself. They sell boxes of dye specifically for root touch-up with a special applicator (these are made to match the colors of all-over dye the company sells), or you can get it all separately at a beauty supply store. The dye won't wash out when you shampoo. I might have talked myself into doing this, too!