Thanks so much for everyone's help! One final question:
I take 400mg per day magnesium (currently Bio-magnesium but citrate in past and oil) as an antispasmodic/smooth muscle relaxant for the esophageal spasms/motility disorder. As noted I also have symptoms of low stomach acid, bile in stomach, gastritis and possible mild gastroparesis/delayed emptying. Other than a 'minor' esophageal motility disorder I have nothing supposedly wrong with me.
Is it at all possible that the magnesium could inadvertantly be making gastroparesis worse, by slowing stomach muscles etc? I don't take it with meals but could it also reduce stomach acid? Or is it all coincidence and the low acid is from legacy stress, and it's the low acid causing the slow stomach emptying?