This is the method I've been wondering about for some time. Due to no one really giving definitive answers to my questions, I decided not to try it.
But if I did, I would use calcium hydroxide instead of sodium carbonate, to ensure the basification step. And at the end, I would use the FASA method to convert to fumarate, then base it again to help clean it up.
Other teks are more well established and practiced. That said, I'd still like to try a dry-tek with acetone someday.
Take a look at this thread:
https://www.dmt-nexus.me/forum/default.aspx?g=posts&t=18699