Get a camera and take a pic of the flowers, with or without the flash, however, flash is better for seeing the color of the trichs, zoom in on the pic until you can clearly see what color the trichs are, then harvest accordingly.
You said one hermied on you and pollinated the other. Why would you keep a hermie in with your flowering ladies to the point of it pollinating your other plant(s)? When you notice that a plant is a hermie, it should be removed ASAP, as not to ruin your whole crop. If it only had a few nanners on it, it's not a huge deal.... nanners usually happen during late flowering and the seeds will never reach maturity.
The resulting seeds from your hermie-pollinated plant can have a 50% chance that they'll be a hermaphroditic plant as well. Those seeds may not grow the plants you want them to.