Hi Frank,
Lots of questions!
First you ahve to decide whether you want to raise hybrid table birds (bred to grow big in a short space of time) There are strains more suited to free ranging than others. Some eat so much so quickly they 'go off' their legs. But they are ready to cull by about 11 - 15 weeks.
Alternatively, you could look at a utility breed (there are many) Each has different supporters and different qualities, but most won't be ready to cull til about 22 - 30 weeks old. Which means putting up with crowing (and potentially) boisterous young stud behaviour!
Do you want to eat the girls aswell, or will you keep the girls for egg laying stock? Another consideration.
You will need to keep the chicks separate from the main egg flock.And also keep the table growers separate from the layers as you may want to feed them differently.
One cock will easily cope with 3 or 4 or 5 hens. You don't want to give him too many hens as you do want fertile eggs.
Another option is to buy in fertile eggs. Waiting for a hen to go broody may take long enough so you may want to consider an incubator or even buying day old chicks.
Sorry I seem to have given you more things to think about rather than answering any of your questions