I usually take my weight in KG (half my weight in pounds) every time. DMSA tastes terrible, so I wouldn't recommend pouring it into water and drinking it.
Unfortunately, I was never able to get a metals test done (I don't live in the States now and the right kind of test is not available in my area). You could do a search for chelation doctors in your area and see if any of them will do it for you. It's better to have the test done by someone who knows something about chelating since there is such a lot of ignorance about heavy metals among medical professionals.