More lift from stock rockers?

Can any one send me a link to a wright up on modifying the stock rocker arms for more lift. I searched quiet a bit last night and did not find anything. I know the kart racers do this some times to stay in spec. I already have a set of champions for my race motor and am going to be getting a set of 1.2 rockers later for my current motor but have an extra set of rockers from my BSP motor just laying around. I know that if I flatten the bottom of the rocker it will add some lift but how much can a person change the ratio of the stock rocker and is it enough to see any improvements. How much do I flatten the rocker arm and how much lift will I gain? Should I use a file or a torch and hammer it down using a punch and hammer? If I use a torch on it should I reheat the rocker and quench it to harden it after I am done? Its going to be a while tell I get ratio rockers as I need other things for my 208 build. Though I would mess with the 2 extra rockers I have laying around as there free and will probably never get used for any thing else as when I get my 1.2 rockers I will again have an extra set of stock rockers laying around.