Forcing a script to bomb, etc.

So... a few miscellaneous questions.

First, where is the current authoritative documentation?  I've not found 
%{!? documented anywhere.

Second, is there a guide to what macros are common on all platforms, 
like %{with and %{without?

Third, can I force an RPM to error with a message is a standard fashion, 
if it finds (for instance) that it's being built with a combination of 
incompatible --with options?

Fourth, is it philosophically preferable to have a package build by 
default with everything, but have the package turn stuff off with 
--without xxx, or build the smallest supportable package, but turn 
things on via rpmbuild --with arguments?

Because I recently got flamed for updating proftpd's .spec file to 
disable most things, and changing the new default behavior to have you 
turn stuff on individually (even though the top of the comments section 
of the .spec file says "this is how you build with everything".... RTFSF 
(RTF-.spec file).

Lastly, where's the documentation on writing and using macros that take 
arguments?

-Philip