cc65: Apple2enh standard binary config q?

Hi!  I'm working on a special project for the C64 and 128 using cc65--even though its target is not quite cc65--and may soon want to port it to the Apple2enh and Atari targets.  This program wants both a very large main memory area and plenty of extra Low RAM via my Cubbyhole optimization technique.  A system file is not quite suitable for the task, as it leaves a 6k gap of memory unused, but my ProDOSi library could use 4k of that and leave 2k for two open files.  I really want that extra memory.  A few minutes ago, I perused cc65's Apple2enh doc and found the binary config.  How do I use it?  Especially, how do I access the disk from it?  I want to use ProDOSi to do the disk I/O, as it's more efficient than the standard C functions.  BTW, you can find ProDOSi at c65 additions - Manage /util at SourceForge.net.