I had something else in mind. My endo told me that he is seeing a significant statistical correlation between T1 and pancreatic insuifficience. As a result the digested food will not be prepared with sufficient encymes from the pancreas. Thus unprocessed food will enter the following stages of the bowels. Causing IBS, diarrhea and a huge loss in unprocessed fat and vitamins and so forth. A constant fatty diarrhea is the result. For this the missing encymes have to be be taken with every meal. The free medication Pancreatin will normalize the situation. It contains the missing encymes. For all T1 with IBS I highly recommend to try these encymes out. Pancreatin can be bought over the counter. It has not many side effects and after some weeks you will know if it is helpful or not.
Your symptoms do sound like your nervous system of the digestive tract has been affected by diabetes. This can be a neuropathy of the digestive system. Apart from good glucose control I have not many ideas. Have you thought about your other medications that might affect the nervous system of the brain and digestive system in the same way? Perhaps they are amplifying the problem?
The following excerpt is just about gastroparesis. I am not sure if the advice is helpful for more widespread neuropathic problems: symptoms of gastroparesis include nausea and vomiting, early satiety, post-prandial fullness, bloating and abdominal pain, but it is also frequently be asymptomatic. Patients with difficult metabolic control should be considered to have a disordered gastric emptying. Nuclear scintigraphy is the gold standard for quantifying delayed gastric emptying, but noninvasive methods, such as 13C-octanoic acid breath tests, exhibit a highly significant positive correlation to scintigraphy. The main goal of treatment is to minimize the symptoms and accelerate gastric emptying. The basic measures for achieving this are improved glucose control and low fat/low fibre diets that are easy to digest. The prokinetic agents metoclopramide, domperidone and erythromycin are successful in controlling symptoms in the majority of patients with gastroparesis due to diabetes. Patients with persistent symptoms or intermittent but severe symptoms may require surgical techniques such as the gastrostomy and jejunostomy. The significance of gastric pacing devices on gastric emptying and specific symptom controls have to be elucidated in further studies.