I personally am a fan of Andy's work because he is a PhD. Biochemist and not a doctor. Doctor's have very little training in biochemistry and often just follow someone else recommendations on how to chelate and often do some really stupid things and some people get messed up. Andy's protocol is all about trying to chelate as safely as possibly.
I know you just asked what DMSA is but I thought I would put my own two cents in about how to chelate in case you decide to follow that line.........