Fencer: Yes. In fact, that's how I would handle vacation days in all situations. If a person runs out of time in a game, and still has vacation days left, add 24 hours to the clock of all games the person has running, including games where it's his opponents turn. This may cause a person to have more than time on the clock than the maximum, but that's ok; resetting to the max (if necessary) will happen as soon as the player moves.

Let me try to given an example. First note that "non"-Fisher Clock games are actually Fisher Clock games. If you have a game with 5 days/move, it's just a 5/5/5 Fisher Clock game. Say I play three games A, BC, and D B. A, B and C are regular Fisher Clock game: 10/1.12/10. D is 5 day/move game, 5/5/5. I'm on vacation, I run out of time in game A. It's not my move in games B and C. Assume I have 48 hours left on my clock in game B, and 240 (max) in game C. I have 120 hours in game D (5 days). If I have vacation time left, my clock is set to 24 hours in game A, 72 in game B, 264 hours in game C and 144 hours in game D. After 2 hours, my opponent moves in game B. 24 hours later, I time out again. Clocks for games A, B, C and D are reset to 24, 74, 286 and 168 hours. 12 hours later, I come back from vacation. I have 12 hours to move in game A, and 62 in game B. If my opponents move in C and D, I will have 286 and 168 hours, more than the max, but once I move the clocks are set to 240 and 120 (their max).

Note that I assumed weekend don't exist. (Weekends are just periods clocks don't run).