I can't really explain how I know I'm an 8 and, frankly, I don't feel the need to have to explain myself before you.
3-8-6 is my tritype. I've done the research, I've read the descriptions, I've looked into myself. There's not much that can really bend that at this point.
But, as I've said earlier, you have helped me explore the various types considerably and have brought up that I might be a type 6 for the first time, and upon reading it -- it is definitely my head fix. It describes why I thought I was a type 5 but in a more perfect/complete way (which is why 6w5 is perfect). But it is not my core drive.. it just isn't.