How to dilute the concentration of extrememly hot chillis

I have come into the possession of a couple of naga varieties. We don't know which ones exactly, but google search seems to confirm that I do have some very hot varieties on my hands and they may average close to 1 million Scovilles.

I was thinking of making some hot sauce, how do I calculate the right ratio of chilli to filler so that I don't end up with something that will kill me?

As reference, the hottest chilli I regularly use are bird's eyes.