Mike I have your conditions, and had stools like yours, but found that with 3 cups of oatmeal for breakfast, bran with my lunch and dinner, I added 'bulk' but have also had to have stool softeners too. If I cut back on the fiber and water, my stools go back to the same small size and shape.
I decided not to take any prescription medications for my reflux due to all of the side effects. I have done pretty well taking care of my reflux with watching what I eat (no acidy stuff, especially at supper), and using an occasional rolaids. However, cold weather, airconditioning can trigger acid reflux and cause me distress, but actually having a snack helps.
Have you tried adding bulk forming foods? I have to tell you that have a bowel movement isn't like running a factory: you can't produce a perfect product by tweaking a few ingredients.
The question is, do you feel all right? If so, why worry about the size and shape of your stools, unless you are constipated and your stools are hurting you, or you have diarrhea that is troublesome, or there is blood in your stool, or your stool has a strange color that might indicate a gall bladder problem, or some other organ problem, or you have frothy, foamy stools that can indicate malabsorption?
Not trying to downplay your concern, just trying to ease your mind that the size and shape of your stools aren't such a big deal, if they aren't causing you any trouble, and that you can't expect to form the perfect stool on demand. In other words, you can be healthy even without the 'perfect size and shape' of stool.
Whoever came up with those dimensions anyway????