Welcome to Healing Well! I think you'll find lots of support here. You've come to the right place--it's a very active forum with many experienced members. I'm sorry about your GERD symptoms, and dry mouth. I suffer from dry mouth as well, but I've never had the need for artificial saliva--I just always have a bottle of water with me wherever I go.
I do think if you could find a PPI that doesn't cause dry mouth. I take Protonix, and looked up the side effects--dry mouth is not listed as one. I take inhaled meds for asthma, and those are the cause of my dry mouth. Maybe you could discuss the side effects with your doctor, and ask for a change in meds.
I'm sure you'll get some ideas from other members soon.
Good luck, Lojan!