The best way to select males is to keep clones of males. Then very carefully make seeds with several males on separate clones of a single female you pick. And then you grow the seeds. Lots of each cross, because genetics will have some dad leaners,some mom leaners,and some mixed stuff of dominant and recessive genes. You smoke test for strength/effect and select other traits as desired. Each male will bring what it brings and you get to compare. Keep the male that makes the strongest smoke, or whatever you are selecting for. Ditch the others.
The thing is, it takes a lot of room/time/energy. And, after all of that, you have to have a clone of the male, or maybe saved pollen, and a clone of the female used to replicate those seeds.
And because pollen is so easy to get everywhere, it is easier to control one male at a time with a variety of females. But, your seed search is then multiplied by each female. And it slows down looking at the male pool.
This was a lot easier when varieties were location locked and you might have access to generational familiarity with a strain. And line worked strains tend to be more homogenized, throwing more similar plants. It's hard to tell what is happening just by looking at a juvenile male.
I just spray and pray.
