Most of the "associations" listed in his CV can be joined by anyone by simply paying a fee. Listing one you founded that is not recognized by any other professional body is window dressing. I've read his work. Most of it is disappointing and he's been accused of inflating his credentials. I'd take anything he wrote with a grain of salt.
I'm not certain what the original poster's point is. That you become smarter after leaving the Witnesses? Giftedness is genetic. It can be cultivated beyond its genetic foundation by use. But leaving a religion, while it may open up areas one's previous belief closed, does not make you smarter. Also, giftedness implies that one can make more 'associations' - associate more factors and facts - quicker than others. But IF your friend reaches the same conclusions you do, but two days later, are you truly better than they are?
And MENSA? I belong to MENSA. It's fun or boring depending on the day and who you're with. But it does not certify you as anything. Stalin probably qualified for MENSA. He acted stupidly.