Seeds take a lot of work to ensure you don't seed ALL of your plants. Here's what I do. First, make sure you bring a spray bottle with 50/50 water+rubbing alcohol mix. Needs to be enough to sanitize your room and kill any pollen that may be floating around still when we're finished.
Remove the females as far from the room as possible. Bring your spray bottle with you, and a couple grocery bags to put your clothes in when finished. Extract the pollen in the room once the females are removed.
Then kill the male once you've finished extracting the pollen. Any kind of light proof jar will work here.
Once you have your pollen in your light proof jar, still inside of the grow room start spraying every surface with the 50/50 mix. We want to be sure there's no pollen anywhere near the ladies. Then, bundle your clothes up in the grocery bags nice and tight, your clothes very likely have pollen on them.
Once you've finished spraying the room, and the male plant, you can leave the room. Don't get near your ladies yet though, take a shower and wash the clothes in the bag as quickly as possible.
Once you're clean, you can go get your ladies and put them back in the grow room.
Around week 3, you'll take a q-tip or paintbrush and dab it into the jar with your pollen. Dab the pollen covered q-tip/brush onto the buds of your choosing, rubbing the pollen covered q-tip on the pistils.
Now, by the time week 8-9 comes around, the majority of the buds you dabbed the pollen on should have seeds.
Now you have the best of both worlds, tons of unseeded smokeable buds, and plenty of seeds to boot. Some good looking plants you have, be a shame if all of it got seeded! But, do what's easiest and best for you.
Also, be mindful of the time and effort it takes to find stable crosses.
You'll need to grow out at least a dozen seeds of your cross. Then, you have to take clones from all 12 seeds. Then, you'll need to flower the seedlings out while simultaneously caring for the army of clones you take from 12 seedlings. Then, hopefully one of those 12 is the stable cross you're looking for. Otherwise, time to plant more seeds and repeat the process.
Once you determine which clones came from the stable cross, now it's time to get seeds from it so as to continue growing it. You have many options here. Colloidal silver is the easiest option. You could also leave some buds on the female plant and stress it until it seeds itself. Silver is definitely best here.
Takes a lot of work, but it is incredibly rewarding.