I usually have that problem when trying to take pictures of metallics but a good camera (DSLR type or a high megapixel camera phone) will normally get them to show up at their best,
Your point on it still showing some gold is partly the reason why metallics are so hard to do and as
AllSeeingSkink said, it's easier to just buy one rather than trying to do a DIY one unless you know where to go for materials as I did to create them, it took me about 15 different batches and about a month on my INSTAR line to get a really good metallic that we could sell and we tried all sorts of different ways of approaching it, except yours
I'm not flaming you though

it's always good to see novel approaches to things to improve the hobby and yours is just another one of these attempts and I salute you for it!
However, since you are already at this stage, the extra wash will probably help fill in the gaps where the gold is showing through, but I'm not sure if it will take more than one coat to do that.