I would also direct your attention to http://www.linuxpackages.net/
This is a site dedicated to Slack packages, and frequently if package A is dependent on B and C, that info, and links to B and C, typically are available.
As a side note, I would also mention Dropline http://www.dropline.net/gnome/
which is a huge collection of common and frequently used packages (>170) Installing Dropline for me has no doubt considerably diminished the Dependency Hell issue, and installation (and upgrades) are really easy. Personally, I think both these sites are worth looking into, and at least for me they have dramatically improved my entire Slack experience. -- J.W.