Went with option three. Here's what it looks like:
cat /opt/somedir/myconfigfile.php | sed 's/\t/ /g' > /opt/somedir/myconfigfile.php.new ; mv /opt/somedir/myconfigfile.php.new /opt/somedir/myconfigfile.php
Just put that in an external command and it takes all the tabs that were added by the grammar and fixes them.
I'm running into the same problem. The workaround doesn't seem very elegant to me and it seems to me there should be a grammar file that works. Especially considering the generic.gm grammar won't allow me to check a key vs. the entire line (these are not the same thing). Anyone have any idea how to get a grammar file that uses spaces instead of tabs?