"He even mentions why some people can take high sulfur products/foods and others cannot. "

I read one article that says that those who are mercury toxic and intolerant of high sulphur foods are deficient in molybdenum.
That seems to make sense, as molybdenum is needed to make enzymes that break down sulphur compounds. Those who are intollerant of high sulphur foods can test this for themselves, by taking one mg a day of molybdenum, then after a week or two seeing if their reaction to high sulphur foods has changed. Sulpur is essential for detoxification. Note that both ALA and DMSA rely on sulphur.

Don't forget about copper. While some have too much copper, others are deficient in it. Copper is essential, for such purposes as forming hemoglobin and energy production.

http://www.drlwilson.com/articles/copper_toxicity_syndrome.htm