I pollinated a few buds in my last grow. (Soil, MH/HPS, FFOF, 4x4x6.5, Technaflora nutes) I thought I was super careful - took the one plant out and several rooms away, painted the pollen on a few buds with a paintbrush, sprayed it with a spray bottle after, etc . The buds I painted were full of seeds as you'd expect. But many to most of the other plant/buds had some seeds or seeds just starting. I use a lot of fans and always have the tips dancing, but again I took every precaution (or so I imagined). If I knew then what I know not I would have just pollenated the whole grow and deliberately made a "seed grow" and had shit ton of seeds. Got around 200 beautiful seeds, but I come across a lot of seed in the other buds. I think it is a little less potent as well because of the seeding.
I applied the pollen as soon as I saw white pistils and they stared transforming right away. I let the grow go to a normal finish. Some seeds dropped out naturally, but only a few. I have a planned grow with purchased seeds going now but the next grow will all be from those F1s (Lemon Kush cross with Blueberry Haze - "LemonBerry") So many strains and so little time :laugh:
That was my experience - a little pollen goes a long way!