Pertaining to meth synth, I've heard from a couple of people that it is possible to add dry ice after reducing with HI (skipping NaOH-touluene-HCl). Has anyone heard of this, and Knows what takes place?
No, that seems utterly stupid, and would not serve any useful purpose.
Do a search for methcarbonate. I suspect this is what you have heard about, regarding mixing freebase meth dissolved in Meoh with dry ice. It is not a substitute for other forms of extraction of meth from the reaction, however.