Great thread!
Making feminized seeds using colloidal silver is easy and cheap.
I have done it a bunch of times using Tiresias Mist.
I made a thread about an auto fem seed crop.
https://www.rollitup.org/auto-flowering-strains/548016-auto-feminized-seed-crop.html
When using regular plants, I spray the whole plant for a week before 12/12.
Then the sprayed plant goes into 12/12 and is sprayed for another week.
Any plants I want the tranny to pollinate I keep out of 12/12 for about 1-2 weeks to let the tranny get a head start.
If your pollen sacks are opening before the other plants are ready to be pollinated, you will be fine. There will be more pollen.
The window to pollinate buds is pretty big. I like to get the buds infested with seeds.
With the autos, I started seeds that were tranny candidates two weeks before I started the seeds of plants I wanted pollinated.
In my opinion the transition stunts the plant a bit so the extra week or two of flowering head start are very beneficial.
I like to let the seeded buds go a long time, until they are falling out of the buds and the bud material is over ripe.
Big, fat seeds always seem to do better.
I will be starting some seeds to make a Blueberry fem seed crop in the next few days. I doubt I will be able journal it real time, but I will take pictures as I go.