Russ, oral EDTA is dangerous and unhealthy. Imo it should never be used. IV EDTA is useful in some circumstances but it is still dangerous, since EDTA not only removes toxic metals, but also removes essential minerals in great quantities. It is easy to develop mineral deficiencies using EDTA, if you don't already have them. DMSA is a good idea since it not only targets mercury, but also lead, arsenic, antimony, silver, bismuth, copper,cadmium, tin, nickel, zinc, thallium, and manganese.
if the body is overwhelmed by mercury, then even very small exposure the other toxins won't be properly excreted.
Take DMSA on an empty stomach, as it is hard to absorb and food will decrease its absorption. Imo it is best taken with an equal amount of ALA every 3 hours(you might want to start with just DMSA though, then add the ALA after 4 or so rounds). Imo a dosage of 25 mg is a good starting point, using it for 3 day rounds to start(3 days, 2 nights). After several rounds of 25 mg of each DMSA plus ALA, you might try incresing the dosages or the duration of the rounds, taking at least an equal number of days off as the number you are chelating. Andy Cutler says taking DMSA in ratios to ALA of anywhere from 1 to 2 to 2 to 1 is reasonable. Since DMSA also causes zinc excretion, it is a good idea to take zinc supplements between rounds(some might say to take it during rounds as well, but I think it might impeded chelation. Selenium also might impede chelation, so imo it is not good to take it during rounds).