Howdy boone, no need to stress, just keep a eye (or a loupe! LOL) on the condition of the trichomes. They start off clear then turn cloudy (THC production), and then they start to turn amber (going into 'couch lock). Base the timing of the flush the plants when the tricomes are about to the level that You want, then start the flush. I flush my plants when the tricomes reach approximately 15% to 25% amber.
Good luck with your grow.
Almost forgot, nice looking plants that You have there!