Leave speedstep on, and the CPU can drop to lower speeds/voltage when it's idle, doing nothing or very little. It will go back up to your overclock speed when load demands it.
1.30v is fine. Higher voltages are OK on Skylake as long as you keep temperature under control, and don't go crazy with voltage. You'll find that with DDR4 memory running at 3000MHz, you may need to increase DRAM and SA voltages for stability, too.