I personally like the 10.5u better, especially as you are saying the sitter is going to be checking BG too. I think going down to 10u, might be a bit heavy handed given the cycles he is having on the current dose.
Looking at the 10.5u he hasn't seen green on it for some time, he got to green on the day DH shot 11u, that cycle looked like a bounce clearing cycle so that combined with the dosecrease may well have been responsible for the greens you saw. TBH I probably would have kept him on DH's dose as he probably had some room for an increase. I think he sees so little green that when he dips his toe into the lagoon he races off to the moon like a scalded cat.
But back to the vacation dose, have you thought about a no shoot number?
Is the pet sitter going to be getting am and pm midcycle tests?
Have you prepared a detailed set of instructions for her/him to refer to?
Are you giving her login details in case she has any concerns and can't reach you?
When George went on vacation, my petsitter got a couple midcycle tests in and I know that nothing puts him off his food

so that made me feel a bit more comfortable about leaving him.