The quick and dirty method for growing a single plant at a time (with a 90% chance of harvesting a female) from bagseed is as follows:

Germinate 4-8 seeds, then grow them until you can sex them (you should be able to do this before they are terribly large - just keep topping / FIMing). Hack the males when you see them (probably about half, maybe a little more as I have noticed bagseed tends to produce slightly more males than females - I think it has to do with stress), and decide which females look the healthiest. I would take the best two or three females and grow them to flower. Things happen, plants die, and this way you will have a backup female (or two). If you get to the point of flowering and still have more than one plant alive, you can sacrifice any extra females as clone doners and use almost every growing tip as a clone (but leave a few tips on the doners just to allow them to perpetuate and flower so you get an idea of their quality). This will leave you with a large single female, and many small clones to keep your cycle going without affecting the yield of your primary mother plant. You will probably also want to take a few clones from your main plant, just in case it turns out to be seriously dank. Hope this helps ...