Wow! You guys are a fount of information! Thanks for the link, Cori!
I soaked my VFFs in water, put on my heavy wool toe socks, then my VFFs and wore them wile working for a few hours. It was work getting my toes in the shoes with those socks!
After a few hours I took off the socks and went for a walk. Four miles with no pain. I think that was the answer. Thank you all so much!
Ah, that explains why I have a pair of 40s but tried on a pair of 40s at the store and they were huge. I tried on all the various sizes they had of that particular model and none of them fit. They all had tiny little toes I could barely squeeze my toes into and none had a foot part that fit. The ones I have are definitely ladies but the toes are so long they are almost too long. I figured their sizes must be totally all over the place and unreliable.
I have scrawny feet, and honestly my VFF's fit my feet really well, which is interesting as I thought they'd be too wide when I purchased them (online) and was rapt they actually fit. This suggests they ARE a fairly narrow fit. So yeah, as the others suggested, try men's sizing perhaps. I'd also try and get into an actual store that sells them (if you're currently buying online) so you can try on the different styles.
I bought my first pair in person, 37s, but it turned out that they were a bit short in the foot as my toes are short and squared off. I bought this current pair online, 38s, and mostly lucked out in the sizing. I believe that I checked here at MDA and the style they are (some discontinued trail model) ran large by all reports. Most shoe makers use factories all over the world so sizes vary incredibly.
I must say that I have been very happy with my Speedo swim shoes at $14 as a nearly barefoot experience. They are so cheap that I got two, one black and functional for my trail walks, one turquoise and cute for looking good in town. There is no heel lift, they stretch as wide as needed, and the sole is fairly thin and very flexible for a good nearly barefoot experience. Not nearly so troublesome as vffs. And no one calls them gorilla feet.