It's not a science. You can use too much water, you'll just end up having to drink more. With a pound of seeds, I'd put them in a two liter bottle, then add a bit of water and shake. The water settles to the bottom and the seeds begin to become a slurry. Keep adding water and shaking to test to slurry for its viscosity. Eventually the seeds will be easily shaken and you'll find a sweet spot where you don't end up with too much water. Use room-temperature water from the tap or drinking water from a bottle, not from a refrigerator. Close the lid and shake, turning upside down occasionally and shaking from side-to-side. Shake hard for a few seconds each minute, resting if you need, but not too long. This really only needs to be done for five minutes. After ten minutes, your seeds will begin to swell and you will lose some of the opiates in the water.
Now sit the bottle upright on the counter and bang the lid with the palm of your hand to allow the seeds stuck under the cap to loosen. Twist the cap about halfway off, to allow the water to escape but not the seeds. Hold it over a cup and squeeze. You can use your index finger to hold the cap if you're worried it might fall off, but it usually doesn't. Squeeze it from the bottom until foam bubbles come out. Rewash the seeds and repeat. You should have about a liter and a half of water after two washes.
If it comes out murky brown, it's probably good. It should have a nutty bitterness to it. One pound is enough for me to "feel something", and two pounds gets me to nodville. PM me if you need help.
