Some AF seed advice?

Just to say what a great forum this is, i've been growing for yearsssssssssss & just stumbled across this place. Anyway on to the question. I've decided to experiment with AF strains (lowryder 1/2 mastserlow etc), i like the idea of the quick turnover (bud in 8 weeks ) & I guess it's something new to do. I live in the UK & currently prices are high for AF strains, I'd ideally like to sacrifice my first crop to go to seed, so i have stock for my next crop & I can get some AF sensi.

What sort of seed number can I expect from each female, no exact science an approx amount would do, this will give me an idea of what my initial investment will be. Thanks.