Am wrong side of 40 and have shoulder length dark brown hair (cool toned). Am getting more grey, three distinct stripes (each side and centre), plus a sprinkling throughout. I can't afford to maintain fancy dye jobs at salon and home dyeing is creating black build-up. Have tried Daniel Field but not quite enough coverage. Would a brown henna work? Would happily live with grey bits coming out a bit lighter brown - just not orange. Any ideas? (Not keen to live with grey bits - it's ageing on me).