It could be done auto, but then you loose ability to do low intensity mining.
Equihash is a bit different than other algos.
So the only thing I need to do is tweak the ini settings of the excavator to get the Sol/s as stated on NiceHash website? Or do I also need to tweak my GTX 1070's clock speeds/mem speeds/voltage to get the 435 Sol/s?
That depends of what kind of card you have. Some have higher clocks by default. And some have better coolers and with lower temp you can get more hash. Also some have higher TDP, which again gives you more hash.
But it is easy to adjust these parameters without using any 3rd party tool.