Well if you are only looking for a few dozen seeds I would put paper bags over everything you don't want pollinated and then hit the ones you want to pollinate with a paint brush or a q-tip.
Any way that will allow you to prevent pollen from going where you don't want it will work. Give the pollen overnight and then spray the cola/buds you pollinated with water to kill any remaining active pollen on the leaves or stems. After you spray, pull all the paper bags off and spray all those buds with water to kill any active pollen that might still be floating around. I generally put a marker on the branches I pollinate so I know what branches have the seeds. Usually I just tie a pipe cleaner around them to mark em.
Probably at least 100 different ways to skin this cat brother, just gotta find what works for you.
Now if you want to know a really cool way to knock up your girls before they are in flower, let Stank share a little trick with ya. You know the preflower hairs that your girls throw out to show their sex? Hit those with a couple grains of pollen while they are still in veg and you can have seeds going in veg. My Hawaiian Mayan Gold is in its first week of 12/12 and she already has 30-50 seeds on her that are probably viable. I hit those back when I pollinated the Northern lights just to see what would happen. They will in fact produce seeds while still in veg.
