Question About Making Seeds PLEASE HELP

I just bought 2 packs (20 seeds) of Early Wonder Skunk (autoflower) and I want to make these my seed crop, so I'm gonna grow all the females and kill the smallest and slowest females, also I'm gonna kill all the males EXCEPT the 2 biggest ones. Now here's my questions:

1) what are the drawbacks of this, for example will I have unpredictable plants? hermies? small buds? slow growth? etc?

2) How many seeds can I expect from each plant? approx. 3FT tall plants?

Thank you

inbreeding stablelizes your strain,your seed count depends on your male alot and how much viable pollen he has,I get hundreds of beans by lightly dusting my gals.Open pollination will get you thousands of seeds with fairly good size plants,,,You can flower the males and save pollen off the boys to dust when your girls are ready.It takes a little over 30 days to make a mature seed so you wait a few weeks into flower before you pollinate

Fist off thank you for the reply second when you say it stablelizes the strain then that's a good thing rite? Also I think I'm only going to have about 7 females and you say it's possible to make 1000 seeds from that?? seems like alot of seeds but I'll be very happy if that's the case.

it depends on how stable the parent plants are. stable parents will throw seeds that are for the most part predictable.they will show different traits between the plants but you are not likely to get more hermies,slow growing plants or poor buds because you did a seed crop.I have done a seed run from lowriders NYdiesel autoflower & out of a few hundred seeds, a few did not autoflower.I had 4-5 different common varities come up regularly including 1 that seemed to have midget dna- the plants only grew about 6-8 inches(diesel lowrider was a always short plant to begin with) Do a search on breeding and backcrossing, both will give you alot to read about.
as for how many seeds on a 3 foot plant? several hundred! insteed of doing all the plants at once, consider knocking up a few ladies & go from their

as far as seed count goes, you will get a lot of seeds
i had a small hermie, bit over 2 foot tall
500 seeds easy, probably a bit more, and that wasn't 100% seeded