I failed to update the package properly.  The correct version is now here:
http://vaxn8.tripod.com/tcfs/NetBSD162/tcfs-20000426nb1.tgz

This one does not hang the system when you change kern.maxvnodes.
But I suspect that's rare.  It also doesn't adjust its vnode usage,
I still have to learn more about the code before I can implement
that.

*clamor* Please let me know what I need to do to get it in pkgsrc.