Be forewarned if you go the 1060 route. The 1060 3GB has cases where the 1050Ti (4GB) will beat it, just because it runs out of memory.
If you really want to SLI, you have no choice but a GTX-1070, GTX-1080, GTX-1080Ti, or Titan-X (Pascal) on current models as NVidia did not include the ability to SLI with any 1050 or 1060 series GPU.