I think what frightens me most about DMSA and chelation in general is that there are very different opinions by even experts.

It does seem to be quite a babel of advice on mercury detox. Some may be from ignorance of those passing the advice. But I think the main reason is that there are several different genetic types of people and they respond very differently to the same protocol. For example, just the ApoE gene polymorphism yields 6 different types of mercury detox biochemistry (ApoE4+4, 4+3, 4+2, 3+3, 3+2, 2+2), depening on what two types you got from your parents. There are probably dozens or more relevant but as yet unknown genes, hence hundreds of subtypes. Therefore no detox protocol will work the same for everyone.

The best is to trust the signalling mechanisms of your own biochemistry, which means to try cautiously variety of approaches and stick with what 'feels' right for you. Your own cellular biochemical networks are by far the best doctor for you. Whatever gets the message down to them which activates their healing power is what is the best for you.