gzip-1.3.5 in Gentoo has a patch to make it more efficient with rsync by using option --rsyncable. Here's a patch to update the man page.
Created attachment 73179 [details, diff] Add --rsyncable option to man page
Created attachment 73180 [details, diff] New man page patch directly from Debian This is an import of the man page patch from Debian project.
added to current patch, thanks