What I sometimes do with Gracie when I know my schedule is going to be nuts is calculate how much a specific dose drops her per hour, then use a dose based on the number of hours I need to cover before I can get to her again for periods less than 12 hours. The dose after that may need adjusting, too.
For example, I know she drops about 200 mg/dL on 1.2 units. If I need to shoot earlier at the next shot, say +10, I'll reduce the current shot by 0.2 (1.2 per 12 hours is 0.1 units per hour). That way, she should be safely shootable at +10, though I test to check. Because she may not read the math books, I'll be cautious with the shot at +10 and may need to slightly reduce it too, based on her glucose level. Better too high for a day, than too low for a moment.
I've also tested out what giving her 0.2 units around +10 does, when I won't be able to test and shoot right at PMPS. It seems to help hold her down a bit until I can do the remainder of the shot. (I subtract what I gave early.) It isn't perfect and you do need to be aware of the potential overlap which may happen when you do this. Very much a "know your cat" situation.
