Need paint match advise from expert auto painter

[rindel]

I touched up some chips on the edge of my drivers door and fender with paint scratch lime gold for 69 mustang (color code i) but the paint was too dark. I went to Sherwin Williams auto paint store and they gave me a closer match but still not an exact match. I went back and the guy gave me some more sample paint and extra black and silver to add on my own. So my only options to mix on top of the lime gold is to add more black or silver to get more metallic. Can someone advise if I can get to the original paint by either adding black, metallic or both? the 3rd mix on the photo is the closest match yet by adding black. Please advise?