I usually score between 125 and 130 in IQ tests. I don't know how close that is to reality, but I believe it's safe to assume I am above the average in the areas that those tests measure (usually deduction/abstract thinking/language skills/memory). I know these tests ignore many important aspects of mental abilities, but that doesn't mean there isn't any truth to them.

About duals with low IQ:
As an NF type I'm supposed to get help in logical matters from my dual, but with the less bright individuals I often feel like I need to help them with logical (mostly Ti-related) matters. Which I don't particularily enjoy. Even if the need for dual functions could get fullfilled with a stupid dual I don't think I'd enjoy their company very much. I love talking about philosophical, political, cultural etc topics, and if I the other person happens to be too dumb to understand the language/terms I use (which has happened) and/or the only thins he has to say are boring platitudes or even irrelevancies I'd rather not talk to them. I need intellectual and emotional intimacy just as well as physical, and low-IQ LSEs are only good for the latter.