Question please about hair color?

Im 41 and totally grey, Id like to color my hair with Roux Fanci-full, had a bad reaction a couple of years ago with a semi permn color so now Im cautious, my question is can I use fanci-full all over my head, is it safe? id tried coffee, tea, sage, rosemary, it just makes my hair look dirty. henna is too orange to me. Is there anyone out there using this product all over? thanks