When we were kids we had a dog like this sadly my dad's a p&^%$ and he just got rid of her. She was just so thrilled everytime he came home, and so was so gentle and submisive.
Great that you'd found a site with tips. Just a couple of things, you could also try. Lower you tone and sound calm, don't over talk to her. Don't lean over her. Also some dogs respond better if you stand sideways to them, rather than face on.
When I worked at kennels, they'd always send me to get the dogs that bit. (grooming parlor clients dogs) The dogs that sank low and stayed back at the end of the runs, I approached by squatting down, talking softly and very slowly going backwards till next to the dog. It never failed, though I looked a stupid plank.
Not saying you need to do this, but just saying just check your body language, at times she pees. Perhaps there is a pattern, you can change.
Good luck with this, so pleased to hear of someone who's willing to work with their dog. Will be cheering you both on.