The actual issue is - vets recommend what they know, and what they have seen to work. Often, in cases of supplements, they don’t know why they work. Most vets aren’t regular readers of online catalogs to see what’s out there, so most really don’t know what feeds or supplements exist, much less how they are formulated, to even make suggestions.
Meaning - they can’t suggest what they don’t know about.
Which means doing what you’re doing - crowd-sourcing for alternatives that may still fit what you are looking for.
If your goal is (near) 24 hour support for the stomach, then 2 doses of Outlast won’t do it
If your goal is support for the stomach AND the hind gut, or even just the hind gut, Outlast won’t do it.
But then why are you asking about alternatives from SmartPack?
If you want to support the whole GI, don’t want a liquid/gel, then yes, I think SmartGut Ultra as a pellet is a perfectly viable option to try. The research supports its formulation, which is more than can be said about a lot of supplements.
The thing is - if you’re using this for prevention, you won’t know if any of these work if there wouldn’t be any issues if you weren’t using anything. 1 colic doesn’t mean there’s an underlying issue.
A series of colics may mean there’s an underlying issue that isn’t related to how he’s fed or managed, and that’s a much better situation to try for prevention.