Please add following neat trick to the FAQ:
Climate has perhaps the bigger impact on map appearance than area itself. To set proportions of terrains more precisely, create multiple entries for same climate, for instance:
11 is swamp here. I made it so there's 2 times less swamp than any other terrain. Tested and works. Use greater number of redundant numbers for greater precision. (Just make sure ratios remain appropriate).
I'm almost sure this trick works for places like day/night sounds, creature hit/death/fire/etc sounds... For instance I have several wolf howls, and only 2 crows. If I don't want my sounds too dominated by wolves, I'll type in crow files several times to compensate.
(not going to happen because I'll use wolves at night and crows at day)
For some reason no one used this trick in Default Notrium.