1060 will last longer than 580, but 580 is more profitable for mining.
But can you mix them?
Yes, you can, actually it's the only way to use 19 GPUs in the mining mobo.
Hi is there a guide/tutorial on how to create custom timing straps? thanks
There are some tips only... you can find almost everything here:
https://bitcointalk.org/index.php?topic=1758267.0some files are outdated there...