Lots of good stuff here (just read thru) a couple of thoughts. Like stated way earlier, when looking for a boy, pop as many as you can and cull down. Liked the one that had the color too it...
Once I've made a choice, that plant goes into the kitchen, where the air is fairly still until I feel it's close enough to cut and basically put in a vase with parchment paper down.
Then 1 female at a time, hand pollenate, when done, let sit for an hr or so and rinse before moving back with other plants.
If your growing in NorCal, don't flower out males outside. Your risking anyone else's garden within a mile and a half or so. Lot of people growing their meds outdoor.