Color help

[TJAugie]

I thought I had some different colors in my stockpile and was going to try and make what I had work. BUT, I can't find any of it except the ONE can of paint I bought.....yay.
So, what I was THINKING was I was going to try and do a subtle marbleized technique paint job. Using black as the main portion faded into the gunmetal/candy purple marble thingy, and silver for the windows and undercoat (again, all colors I thought I had).
I was going to also do the right thing and test it out on the scrap lexan that I had from cutting out the new body I just picked up. But again, I can't find the paint. So let me know what the painter's thoughts are before I maybe spend money on 4-5 more cans of paint just to have it look like garbage.
Thanks for using your imagination everybody.....lol. I actually did for once, look where it got me. Now I am kinda making this work in my head and I am digging what could be a nice subtle combo that would take a 2nd or 3rd look to notice.