Paul- just wanted to add a couple of pointers we got from a trainer on Riley.
As far as teaching gentle mouth, she told us to keep a treat in a closed fist, and put a tiny dab of peanut butter (or butter in our case, as our DS has a deadly peanut allergy

) on our thumb knuckle. This will get the pup interested in mouthing your hand, but you only open your hand for the "real" treat when there is licking or sniffing ONLY, and no teeth at all.
Second, she taught our son (he's the one Riley likes to nip at the most when it comes to petting excitement) to only approach Riley under the chin for petting, and only once she is totally calm and not bouncy.
OH YEAH.. and another thing she showed us is that when Riley does do something with her mouth that we don't like, to YELP really quick and short like a puppy. She could do it REALLY high. I can do it (not sure my hubby has that ability, lol- and she told DS that a higher-pitched "OW!" will work too), and it works WONDERS on Riley. Totally throws her off guard, and she would immediately lick the trainer after instead of biting. Pretty neat!
Anyway, these are the things I've learned and maybe they can help you, too. How is your pup doing this week?