Helen has a pretty stable foot, unlike mine, so she doesn't need a lot of arch support. She has occasionally gotten numb toes though from riding. It hasn't been a major issue for her, but a regular minor annoyance.
The first thing Sean and Helen looked at was the saddle choice and positioning. Helen had her eye of a Specialized women's saddle called the Jett. Sean agreed it would be a good choice and helped her pick out the right width (saddle comes in 130mm, 143mm, 155mm widths). Helen went with the 143mm. She had been using a Selle Italia Flite Gel, with the nose angled way down. When they put the Jett saddle on, they put it flat and Helen's hips nicely rotated with no pressure or discomfort. Sean helped set the height and fore/aft positioning just right. Helen also got immediate improvement in her hands and arms because they were no longer having to support so much of her weight. She was actually able to rotate her handlebars down and have better positioning in all three handlebar positions (tops, flats, drops). Successes!
Sean then looked at Helen's knee tracking and asked her about the foot comfort. Upon looking at her feet and arches - he had her try the Specialized BG footbeds. Not the highly supportive green ones like I've been using, but the slightly lower arched blue ones. They still have metatarsal support though, which helped even out the pressure in Helen's shoes. Helen's knees naturally track pretty well, but the footbeds did actually help make them just perfect. Successes again.
Given that it is November, Helen is mostly running and strength training, but don't be surprised if you see a cute little girl on a green Cannondale saying hi and waving at you as she flies past you up a climb next summer.