The only real way to get all kinds of information about kernel parameters is to read the includes that those variables come from, in Mac OS X the list starts with
- sys/sysctl.h: definitions for top level identifiers, second level kernel and hardware identifiers, and user level identifiers
- sys/socket.h: definitions for second level network identifiers
- sys/gmon.h: definitions for third level profiling identifiers
- vm/vm_param.h: definitions for second level virtual memory identifiers
- netinet/in.h: definitions for third level Internet identifiers and fourth level IP identifiers
- netinet/icmp_var.h: definitions for fourth level ICMP identifiers
- netinet/udp_var.h: definitions for fourth level UDP identifiers
It's a though read! :)
Also there's no standard way of tuning all these kernel parameters, everyone has different needs and Mac OS X will come preconfigured with values that'll meet "most" but still will leave some people with the need to tweak it, as you want to.
What I normally do if I want to tweak a kernel parameter I don't know much about is to Google it up, read as much as I can about what it does and what other people are doing and why, and from there try a value that can work from me.
Sorry that this is not the easy answer you were looking for, but I hope this will help you find the answers quickly :)