Bleach or use a light hair toner???

My natural hair is very "salt and pepper" with it being mostly white on top, and and medium brown in back.

For years I have been coloring it a light brown color, but got tired of my roots showing so obviously after 2-3 weeks. So I bleached it using Quick Blue, but it came out much more yellow/orange than I wanted, so I went over it with a violet based Medium Blonde to tone down the orange. Now, it is a wonderful honey blonde color and I love it! The question is how to keep it like this. Will I need to bleach and tone each time, or is there a color I could use that would lighten the dark parts of my hair while toning the gray?

TIA!