I'm sorry, which post?
The original post is a description of how to crystalise meth after a reductive amination of p2p. After this there is some vague descriptions in the comments about rectification but nothing about L-Meth specifically.
Sorry can you please clarify what you mean by "L-Meth" or point me to #step 1 where you are saying we need to get L-Meth (aka the least active isomer).
If what your saying is true, we can make d meth from Vicks inhalers. So yeah that would be a huge plus for your site , and clandestine synthesis in general.