I've been riding ACEs since I started skating again and I love them. I don't like oose trucks or tight trucks, I like trucks that turn.
ACEs are a truck that turns deep and responsively; how loose you ride them is up to you.
Bushing-wise, if you want to retain the stock geometry you need to keep the bottom washer in place (not sure how big of a deal this is as it changes when you tighten them anyway), using the top washer is up to you and your bushings.
The best combination I've found is either hard bottom BARREL bushing and a bones medium top or a bones HARD bottom with a medium top. The kingpin hole in the hanger is BIG, too big for Khiros, they will end up blowing out if you ride loose (mine did). If you choose Khiros, go with the aluminum inserts as they retain the stock geometry and don't need washers.
I tighten only enough to take up the slack between the hanger/bushings/baseplate, this usually means the kingpin nut is flush with the end of the kingpin bolt (think factory tight).