Again, thanks everyone for your suggestions. Here is the latest.
I thought I should update you all on Mr. Poopy Pants. It's been a long, soft road & it continues.
So since June we've been trying all kinds of stuff
Enzymes
Fiber Powder (Metamucil)
Pumpkin
Rice & kibble
Chicken & Rice
1/2 Flagyl + kibble & rice
immodium
different food
more different food
sulfasalazine
Flagyl
So in between we took blood for mal-digestion; this was the one time that my Capone-freak-mom-ness paid off. Because I've been paranoid that his behavior oddness is associated to his Thyroid, he's got a good yearly baseline for bloodwork. That and I'm scared poopless of heartworm. So my poop, pee and blood sampling for him have paid off.
I remember a post from MissKiwi where she said that bloodwork is not a $ maker but an insight into the dog's health.

(REMEMBER THIS PEOPLE!)

In my case, soooo true.
Long story short, the test for mal-digestion proved nothing right now at least. We'll wait until it does. Even the vet thought he would have bigger problems. We were fearful of SIBO or EPI. To quote a post to a friend, "damn, I JUST got a call from the vet. He too said "I thought he had EPI too" but all his levels are in the normal range. So he thinks it is just IBS and his issues. Now I think we're chasing ghosts. One of his levels were a bit elevated by only 3 points, everything else normal, which means it could be pancreatitis but the rest of the numbers don't fit. -*then came a bit of explatives to my friend from frustration*- So he's healthy. Meanwhile I felt like he's wasting away.
So after this blood visit, he was prescribed Tylan powder 1tsp followed 1 week later 1/2 tsp daily
I decided to go the route of Hill's iD food low fat solid & wet. This way my vet knows what the food 'does' and how it should 'work' in his crazy f-d system. I don't want him to be on it forever, but for baseline, I'm ok with it.
This last week, I kept the vet updated more than usual. After all I'm tired of the center of my thoughts being Capone's poop. We've switched up things. Even my uber experienced vet consulted 2 other vets in the practice. Now we're doing:
Cipro 2 per day
Panacure 3 day treatment & repeat in a few weeks
1/2 tsp of Tylan 1 a day
He is doing well on the food and meds, interestingly even for him this has never been a problem. No stomach upset and I think he gained a pound. I keep waiting for worms or rice things to come shooting out of keester but nothing so far. His poop is still soft serve and the color is not good. The horrific smell comes and goes. Today it was not too bad but tomorrow, who knows.
...and thus the poop story continues. More soft serve to come. Until then...