That I understand thanks man perfect . Hats off brotha . I get it how can we find out what they are ? I notice most seeds banks or imOk....so the "S" stands for 'Self' and the number indicates the generation. So lets use this example Joe....I make some S1s from my Blue Dream and send them to you. You grow one out and you love it and decide to make some feminized seeds. You spray it with STS and she sprouts balls and BAM, KJ just made some "S2s". Now you give some of them to Guy Cavellero cause you think he might like some and he grows it out and loves it. Guess who now wants to make Fems from that Blue Dream to keep around for a while.....yup, and me makes him some "S3s". Each time someone else makes an S from that same lot, it will add another higher number.
Supposedly from a few things I have read, after about S5s and S6s, you can start to see issues with the stability of the genetics (according to some).
Now as far as what you can cross with an S1, well you can cross just about anything. Keep in mind you will generally need it to be a male that you cross it with, but it really doesn't matter what "F" you cross it with. It will all work of both parents are strong.
Not looking in the right spot doesn’t show its linage V