I am by no means a Vans expert - these are my first pair!
From the sizing chart they are men's sizes and 1.5 smaller for women which I didn't realize when I ordered. So what Nordstrom listed as a 6 is a men's 4.5 (not a 4 as I would have guessed from Dr. Martens and other unisex brands). I am usually a 5.5 with wide high volume high arched boxy feet, but I often go with women's size 6 because 5.5. wide is so hard to find. I'm ALWAYS a 4 in unisex/men's shoes, though, and I should have gotten the women's 5.5 or men's 4 in these babies.
This pair was a bit loose all over, and I read online that this particular style (the Beatles version) runs a little big. If you are a true 6.5, I think you should order your true women's size, which would be a men's 5.
Mine are canvas. More experienced people might chime in about stretching but these seem more sturdy than other canvas shoes I've had.