I would hesitate on the SmartPak GI supplements, specifically for their use of fructo-oligosaccharides, especially if the ulcers you’re fighting are glandular. In that case, you want to protect the mucosa as opposed to preventing splashing.
This is maybe the best review of research on ulcers I’ve found so far, and it mentions that certain pre-biotics actually might be doing more harm than good.
https://www.sciencedirect.com/science/article/pii/S1090023322000454
" However, prebiotics, such as fructo-oligosaccharides, are degraded to short chain fatty acids, such as butyric acid, by microbes and may be harmful to both squamous and glandular mucosa ([Cehak et al., 2019] "
Dr Ben Sykes is maybe the most well-regarded vet on equine ulcers. He has a terrific FB group on ulcers, he answers questions.
https://www.facebook.com/equineulcerresearch/
He recently presented at a vet meeting my vet attended. In addition to Relyne (or GutX probably), he recommended ProTek GI. He did consult on this product, so some skepticism is valid.
My vet used it on a horse with terrible pyloric ulcers that never fully resolve, they just get better and stop being clinically problematic. They put the horse on this and he scoped clean 2 months later. This was the type of hose regularly being turned out for pasture rest for a few months and GG treatment of several months to resolve the ulcers.
It’s expensive. But it also seems to combine all the good ingredients, including Pectin, Lecithin, Beta Glucans, Calcium Carbonite. If you’re feeding Relyne and Assure Guard Gold or Smart GI ultra, it’s less, but not by much.
I’m going to try it on my mare who I’ve turned out on pasture and worry I’ll have to retire her pyloric ulcers are so bad. I’m hopeful.
Oh Dr Sykes also ran some titers on Gastrogard and said you only needed to wait 30 minutes before giving hay after GG, not one hour. He was the researcher who originally came up with the one hour. It’s a small help, but I’ll take it! And that that first feed is the best time for the alfalfa hay.
He also mentioned that you do not need to taper GG, but you should give your horse two full days of rest after treatment which I thought was interesting.