This is terrible, I tried it for lulz in the cloud (wasted free credits), and it failed to do anything significant, you may find https://github.com/nanopool/ewbf-miner is the better implementation if you want to try, seems to run best on nVidia kit in my experience.

If the GPUs are based on the same architecture, it's usually enough to just look at the number of CUDA cores to see which one is better (but don't forget to look at the memory requirements for mining a certian cryptocurrency). M60 and K80 are different generations though, and if you can't find any info about their hashrate on the internet, you'd have to test it yourself. Considering the very high prices of these high-end GPUs like M60/K80, you might want to consider buying a gaming card like 1070/ti, 1080/ti, 2070, ...