Yeah, letting 'em dry at the end doesn't seem to be a problem - IF they are sitting in flush (very low EC water).
But if you are confident with full automation, I'd let it run as normal.
I was thinking to program the timers: 12/12, 11/13, 10/14, 9/15, OFF, OFF - But only if you were going the let'em dry route and harvesting as soon as you got back. Running Auto as normal keeps all your options about harvest time open.