I believe the Rome III criteria for IBS-D is 3 or more bowel movements per day and for IBS-C is fewer than three bowel movements per week.
With IBS one rarely has instant or real time reactions. The reactions usually don't appear until the offending substance reaches the particular part of the colon where problems are occurring which can take from a 6 to 36 hours.
Your symptoms sounds a lot like mine us to. The ribbons are indicative of bowel spasms. The biggest improvement for me came with some dietary changes. In particular removal of cereal bran from my diet, a major decrease in insoluble fiber and increase in soluble fiber and removal of foods with excess fructose (apples, pears, melons, grapes, honey, etc). Have you ever tried reducing your consumption of foods with excess fructose (i.e more fructose than glucose)?
Leaky gut is a permeability problem with the gut which is typically associated with things Crohn's or celiac disease. There is nothing to indicate it is associated with IBS. As I recall even with leaky gut there is little evidence that dietary intervention is beneficial.
I have been experimenting with melatonin. It is known that it plays a role in sleep but over the past couple of decades it has been found that there is 10 to 100 times as much of produced in the gut than is found in the blood stream coming from the pineal gland. It is now known that melatonin plays a major role in the control of bowel motility and sensation. There is some good clinical evidence to show that 3 mg of melatonin taken at bed time can reduce urgency and pain. I have had pain with my IBS-D for decades. Recently I tried melatonin. After about 10 days the pain and urgency were significantly decreased. I am rather amazed at how well it works for me. Some time soon I will post an overview of the research on melatonin and IBS.
-------------------- STABLE: ♂, IBS-D 50+ years - Science of IBS