You need at least 6 weeks for the seeds to mature. So the ideal time to pollinate would be day 20-30 of flower. :)
The above female is my auto, and used as an example of white pistols. But I would suspect they are still in a good window to pollinate. But the seeds then would be semi auto. Meaning some seeds would be photo, and some auto.
Oh I thought you meant "fully" as in until they are fully matured (nearing harvest). You just meant once the flowers are full grown. :)
Interesting info! Some day I will try this...