I would spring for it. It’s cheap (vet visit cost more than the actual procedure). But do try to investigate the management too. Ulcers are almost always management.
I did it about six years ago on a horse we owned for 20 years, would do it again. Symptoms were rapid weight loss, colics (owned this boy for 20 yrs, NEVER had a colic), fecal water, completely runny manure, loss of interest in food. We pursued just about every diagnostic tool available to us: no ulcers, x-rays fine, nothing explainable. Tried him on metronidazole, improved for a week before tanking again. No improvement on Sandclear. The last ditch idea was to try transfaunation. He was much better within a few weeks. Still not 100% but better.
Vet’s best guess is inflammation (colitis) in his intestines disrupted healthy gut flora, and that “undigested matter” was further scraping and inflaming the gut.
For what it is worth, we later discovered he had Cushings about six months after the fact. He’s managed on pergolide but still occasionally will have runny manure. Good weight now though. He’s 27.
I’d investigate the ulcers. Has this guy been put on a 24/7 roundbale yet? I’m convinced that this is absolutely a “miracle cure” for ulcers – and way cheaper than two courses of Gastroguard. Even if you factor in purchase of Hay Hut.
Secondly, has he been turned out with a buddy yet? 24/7?
With persistent ulcers, if it’s not pain, it’s because the horse is stalled and isolated. Something to consider.