In short: Is there a way to tell preview-latex to NOT use pdflatex instead of just toggling TeX-Pdf mode every time I want to re-generate previews?
I have a somewhat odd setup. AucTeX + GNU Emacs 24 on Mac OSX 10.6.8, operating with Skim as my pdf viewer.
I am using a makefile for document compilation that calls latex + bibtex + simpdftex to generate a PDF with synctex enabled. (I use psfrag and .eps files which is why latex is used instead of pdflatex). When Auctex is in TeX-Pdf mode (C-c C-t C-p) I can use synctex for forward and inverse search and C-c C-c and a Make command for quick compilation. (Without being in TeX-Pdf mode, forward-seach (C-c C-v) stops with a .dvi not found error) So far, everything works great, as expected.
However, preview-latex doesn't like this setup. When in TeX-Pdf mode, preview-latex wants to use pdflatex as the compilation command, but this doesn't work with my document and errors with a no images found. If I turn off TeX-Pdf mode, re-run preview-latex (C-c C-p C-d), PNGs are created and correctly placed in the document.
The Preview LaTeX Command customization option seems to be specifically related to what is inserted into the tex document and not the external compilation tool.