I strongly recommend that you check out this interview with Cutler and Dr Dan Pompa. It provides the basics and explains some of what you've experienced. http://www.healthcentersofthefuture.com/DrCutler/
The mice in this study did not do so well when they received infrequent ALA. NOtice they ended up with more Hg in the brain even though they excreted more than controls. Cutler explains why. http://onibasu.com/archives/am/74605.html
i strongly suggest that you consider taking generous doses of antioxidants--vitamin C, E selenium as well as magnesium and zinc. Much more could be said!
The big chelation groups at Yahoo are also a good resource.