I believe the reason DMSA and DMPS worsen Candida is because they both chelate heavy metals.
I've been taking DMSA for 2 years now in order to chelate mercury. Every time I do a mercury cleansing about a week later I will have a yeast reaction (This was an important clue for me to confirm my suspicions of a connection between mercury and yeast).
However, after continuing the DMSA for 2 years, my yeast reactions have become less and less (including the ones to food).
The temporary worsening was worth it for the overall benefit.