Good for you for doing your homework! Here's a little more for you...
Bill's Box Turtles has a great page, complete with photos and illustrations, on sexing box turtles, so try there first: verbal descriptions are tricky at best.
Tess Cook's website has great information about proper diet and ideas for what, and how much of it, to feed box turtles. Her site is Boxturtlesite.org.
I feed my easterns a variety of foods, usually making up a batch of 'salad' once a week or so and feeding every 2 days during the warmer months. They've just come out of hibernation and haven't been interested in prepared food, but have been stalking worms and slugs.
The salad ingredients vary, but the ratio of protein, vegetable, greens and fruit stays about the same, and since they're outside year round they can do their own hunting, too, as already mentioned. They need variety.
Regards,
Stephanie