UNIX for Advanced & Expert Users

I am using the ZLIB_VERSION "1.2.3" . The memory requirement for Zlib/GZIP compression is stated as


/* The memory requirements for deflate are (in bytes):
(1 << (windowBits+2)) + (1 << (memLevel+9))
that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values)
plus a few kilobytes for small objects. For example, if you want to reduce
the default memory requirements from 256K to 128K, compile with
make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
Of course this will generally degrade compression */

If I can make changes to these macro to reduce memory consumption,
MAX_WBITS=14
MAX_MEM_LEVEL = 7

How it will effect the GZIP compression method ?
Now what would be the memory requirement for window size, the size of Heads of the hash chains
and prev pointer which is basically linking to older string with the same hash index?

Also, what are the various ways to reduce memory usage?