by that i mean, what will give me most hash, for each watt i use
Anyone??
Reduce core clock as much as you can without affecting hash rates.
Then increase memory clock until you hit memory errors.
Then reduce core & memory volts until the GPU gets unresponsive/unstable.
That's how you'll get the sweet spot for your GPUs.
Each & every card is different even if they are identical. So, tune accordingly.