[plt-scheme] Boehm gc in embedded scheme application

I'm considering embedding MzScheme into a C/C++ application.  The
application has an interactive part, so I would need to use the incremental
mode of the Boehm collector.  I'm concerned about bad interactions between
MzScheme and the gc in the following circumstances:

* scheme calls C code, which uses gc_malloc
* C code in a separate OS thread uses gc_malloc

Can anyone tell me if either is problematic?

I'm also interested to hear suggested best practices for using mzscheme in a
C/C++ application that also uses the Boehm gc.

Thanks!