If I had an S7 & if it was a 4.86TH unit and if I was going to overclock it I would adjust the psu to be 12V + 5% (12.6V) at the PCIE connectors then take it up a step at a time, check for HW errors and keep a close eye on the temperatures. Theoretically from the BM1385 data sheet about 725MHz should be possible, but with them reducing the spec for some Miners that is more uncertain than usual.

The above just my thoughts and in no way a recommendation, Overclock at your own risk. I am sure someone will hae tried it and have some real experience, but may not share until Warranty has expired.  

Rich