I ALMOST FORGOT TO MENTION!!!! that I don't think they do dosing on a 12hr schedule when you kennel there (although I don't know for sure). Most vet offices, as far as I can tell, give the shots within the first hour they open and then within the last hour before they close. I always just assume that they're giving Motska's shots at 8:30 am-ish, and 5 pm-ish. (When I go to pick her up after work at 5:45pm, she's already had her afternon shot -- and I seriously doubt that somebody got in there and did her AM shot at 5 am!!)
So when you kennel your baby there, you may want to adjust your dosage down, or give them a slightly higher carb food to feed her. (I give them the higher carb food.) And if you have any special instructions, they're pretty good about that. I've got a printed instruction sheet that I give them every time Motska is kennelled there, so they can put it on Motska's clipboard -- ex: no shot if her BG is below 200, a photo showing how to measure the dose, since she only gets .2u and we're using U100 syringes instead of U40 syringes, etc... When I picked her up yesterday, they told me that her BG had been 85 when they tested it, so she didn't receive a shot.
If you absolutely HAVE to keep to a 12 hour schedule, you may want to try to find someone who can come to your house to do it....