I may have gotten confused about the matter. I'm familiar with the gut cycle of inorganic Hg being metabolized to MthHg by candida and similar gut organisisms.
There's certainly plenty of folk warning about methyl-compounds compounding an amalgam-related illness,
But to be honest, I think much is secondhand heresay as opposed to treatment-based knowledge.
My own experience with a methylmercury-containing b-complex vitamin isn't negative-
At least, I didn't recognize any worsenings of mercury-related symptoms, other than the exacerbation (uncovering) of higher EFA needs.
You leave me wishing to find classes to take in this arena of study, Fervy. ;)