I use Karo mixed with LC even when Buzzy is in the 40s. He has an allergy to chicken, and it's the best method for me to ensure he's not exposed to an allergen.
At this point (for my cat and with the data I have on him specifically & how he's responded to things), if I'm around to do all the testing and such, I do LC only unless he touches the 40s, then I do Karo + LC to make a HC - he seems to respond well to it so far (KNOCK ON ALL THE WOOD!!)
Edit: I should actually be specific - what I have is light corn syrup - it isn't Karo brand.
Edit again: and also the above is only when I can be like ON him w/ testing. If I can't be there or need to sleep, I'll do LC + Karo earlier on. But, the point is - I have to avoid allergens & he's also still recovering from falling into this newly developed allergy, so I try to be really consistent in what food he's eating
Last edit I promise -- and of course -- Buzzy is newly diagnosed, whereas I know Panic was diagnosed a while ago

so our number thresholds are different.