hello yelram,
i personly dont prune unless i realy have to, normaly i get around a once on the top cola and about 1/2 ounce from the smaller lower sites if i am luckey, sometimes its a bit less around a ounce in total, trimming your plant down to size at the right time will give you a lot more budding sites but on the whole they are conciderably smaller, contrary to this all my grow this year has been cut back realy heavy and if things go well and they finish in time before jack frost sets in i shall have a wonderfull harvest one of my plants is banging on 7ft and that was cut back to about a foot tall , so a lot mate depends on your growing inviroment and the amount of light its getting, i will be starting my indoor stuff again soon, as there fitting me a new stairlift at least then i will be able to get back in my grow room, and grow me some winter stash.
peace mate.......................... happy ...............