I only have feminized seeds, and only grow one plant at a time. I am thinking of stressing my plant into becoming a hermaphrodite in order to harvest pollen to store for later use to produce seed stock, and for use in hybridization in other lines (I have 6 strains that I like). I would prefer to go this route, rather than have to expose myself to ordering more seeds.
My question is, how long can pollen be stored effectively? Also, since I am growing only one at a time, I plan to introduce the pollen only to lower branches, so I don't spoil the whole plant. What is the best time to introduce the pollen (minimum time needed for seed maturity)?

Pollen lasts for a long time, they have found pollen that are still viable that are millions of years old, i'm not sure if marijuana pollen lasts this long but i believe that if kept in a dry place that it would probably outlast your growing operation. You could pollenate the bottom portion of the plant to produce seeds, and it wont affect the rest of the plant giving you beautiful bud to smoke. Good luck with your breeding.

dry & refrigerated 3 months or so, it takes a minimum of 4 weeks to mature.
Chemicals are used to stimulate pollen producing flowers.
How to make Colloidal Silver to make Feminized seeds

you should never use feminized seeds to breed with as you will get hermies...the technique they use is kinda like your talkin about so you could do that with a female from reg seeds just not feminized...its always best to just clone feminized