thinking to get one more card so any suggestions ? PNY 1060 6GB OC GAMING Edition or Gigabyte Windforce OC or MSI GTX 1060 6GB OC V2 ?
in order to get more sols you should oveclock your memory as well, not only core, good and pro[erlu overclocked gtx1060 can pus around 330-340 sol/s, which is about 10% more then you have
As you commented, I changed and tried in different ways & I got 325sol/s with Hynix memory

core +180, mem: -150, power: 90%, on windows 7 with EWBF, but it crashes after 10-20mins (only programme is crashing not GPU).

Core +140 Mem +540 PL 90%, Hynix 3GB, using DSTM 0.58 and getting rock solid average 314 sol/s