Until now I had TeXLive 2011 installed and could successfully modify my memory settings using this solution with the TextWrangler approach to the question Memory settings with MacTeX - Which texmf.cnf to modify. After switching to MacTeX 2012 this doesn't work for me anymore. I already tried completely uninstalling all TeX-files and reinstalling only 2012, but that doesn't change anything.
Maybe this are some clues:
When I try to modify
/usr/local/texlive/2012/texmf.cnfin TextWrangler I get , but it lets me change the file anyway after clicking Unlock.
sudo fmtutil-sys --allruns just fine in the terminal, but I still get
TeX capacity exceeded, sorry [main memory size=3000000], when LaTeXing my document, though the
texmf.cnf-file is definitely changed.
Well, up to a value
main_memory = 12000000 I am able to increase my memory by using this approach. Higher values don't seem to be possible. This solves my current problem. But as one is supposed to rather change the
/usr/local/texlive/2012/texmf/web2c/texmf.cnf I'm still happy about any clues or even an answer regarding my original question.