Hi jimmyt,
The miGen process is done using Maya, and the version of Maya would
be chosen according to the scenefile's version-- if the scene was saved
using Maya 2008, for example, the jobtype will try to find that version
on the worker. Have a look at the stdout/stderr logs of your jobs,
and you'll see that happening in the initialization stage of each subjob.
Because the miGen jobtype uses maya in "-prompt" mode, and not
the simple command line "render" command, there really isn't an
easy way to pass a command line option such as "-rl".