Any time you miss a shot for whatever reason, there's at least 24 hours between shots. You can adjust your shot time with no problem since you're beyond the 12-hour window. If you plan to shoot at 8:00 and at some point you want to get back to your previous shot time, you will have two options. You can move your shot time by 15 minutes at each shot time until you're back on schedule. Alternatively, you can move the shot time by 30 minutes once a day until you're back on schedule.
FWIW, my kitty would not let anyone, and I do mean anyone, except me test her. I had very experienced pet sitters -- they were vet techs who worked in a feline only practice. They could shoot -- mainly because there was food involved -- but only Gabby's mom was allowed to test. I would reduce her dose in order to insure she was safe since my pet sitter was shooting blind. You've welcome to look over Gabby's spreadsheet to see what I did. (Most of the time I was traveling is grayed out.) We're happy to help you figure out what a good dose would be if you're having someone else shoot.