Re: DMPS vs DMSA, safety?
You are right. The information about chelators is often confusing and too often contradictory. I've heard people describe improvement (or have experienced improvement myself) with major chelators, like DMPS, DMSA, ALA, Cilantro and Chlorella. I think that any of them, properly used, can work, and any of them can be risky if used improperly. I would choose a method which other people have used successfully and use it.
It took me 6 months of Cilantro and Chlorella to feel improvement. My friend took about the same amount of time to feel better while using the Cutler Protocol. Another friend is using ALA only, but she hasn't been doing it for very long.
Side effects vary a lot while chelating. Some of your current symptoms will become temporarily worse during a chelation round. You will likely feel tired with emotional issues.
Other people seem to have the opposite reaction. They feel better while chelating and have the kind of reaction described above when taking a break from chelating.
Your severity of reactions should gradually become less and less as chelating continues.