I faced that problem too with my bareminerals, so I had to go for the lighter of the two that they sent, when I thought the first one would match just fine.
BTW isn't this foundation mineral a nockoff of bare minerals?
Cosplay list for 2015
Lightning (original outfit) - 80%
Casual Fem!Shep/Jane Shepard - 100%
Batgirl - 10%
Boston Comic Con