If I were to not run any guilds in a war, would my offensive spells only last an hour?

I realize I won't be able to cast self spells at all, and the duration of the offensive spells will be shortened, but will it go all the way down to just 1 hour long?

I realize this is easy to test out, especially since I'm a dorf and could have easily razed all my guilds, ran the test, then rebuilt them, but I haven't yet and we're about to enter a war. I don't want to raze a bunch of guilds if it will lower my offensive spell duration to 0-1 hours