Let's handle this right - first, to get that number up as quickly as possible requires a simple sugar such as Karo, honey, etc. Not a large amount, but a good 'dollop' - 1/8th tsp roughly first when you're that low. Simple sugars start absorbing as soon as they hit the mouth where any type of food including gravy takes hitting stomach acid and digestion to begin raising glucose. That's why candy is recommended for human diabetics when they start a hypo run - the simple sugar acts fastest. You don't want to send kitty to the moon with the sugars - your goal is to bump them enough to get back to good numbers. After you've given any of the sugars, THEN do gravy or even just med carb.
I know this above isn't exactly what most holler here but after having KT and Doc AND walking many hundreds of cats up from a hypo, this is the quickest and safest way.
Lyane, you're already handling this one - I mainly posted that above for your future reference.