How does the base defense work?

[Triggerfisk]

First off, I love this game. I've been binge playing it over the last few days. I'm left confused and a bit frustrated at the base defense aspect of it though.

I'm at night 40 or so now, with 4/7 defense structures built, plus a post with 10 queens in it (total base defense stat 61.2). I don't see any change in the nightly raids, though.. Every third night or so, they steal maybe 8-10 items, and I have no idea how much of an effect my base upgrades are having.

Do the nightly attacks scale over time, and I'm just not building quickly enough / advancing too quickly through the nights to stave them off? If so, I -really- wish the game would not advance me by 1 night whenever I leave and come back, because it discourages me from playing unless I have at least an hour free. Why does it even do that?

Does the defense stat reduce the amount of items stolen? Does it reduce the chance of a nightly raid? Does it matter *which* defenses I build up, or is the base defense stat the only thing that matters (for example, does a Bed Wall (18) do the exact same job as a Board Up (6) + Chair Bulwark (12)?

If the game would show me some more information about the nightly attack and the effect of my defenses, that'd clear up the confusion and make base defense feel more meaningful. Right now, I seem to be losing crucial materials left and right without knowing if it's even possible to decrease the material losses or stop the attacks completely.