Play with 'sbbuilder'. It's a perl script, so "help" is "--manual" as in: sbbuilder --manual | less
It's better by far to test-build from your script locally, but packages aren't what's uploaded anymore; the build scripts, etc. that end up in <package name>/src are.
The most recent thread in Packager Training and Help
describes how to set up a local build environment that's nearly identical to the buildbot itself. The main difference is that you'll need to install build dependencies locally, while the bot installs anything listed in MAKEDEPENDS on its own.
Thanks for asking about this. The Packager Training and Help area is not much used, but was created after the switch to the new build system -- so there's little stale info there, if any. It's the best place to ask anything related to packaging procedure.