Spiral staircase issues

Hi BA. I’m currently trying to create a spiral staircase (like in a tower/lighthouse). I’m having a little trouble figuring out a method that gives the correct stair pattern. The best result I’ve gotten is from using duplifaces, but it’s still not 100% right. The steps all noticeably tilt down on the outside. This can’t be corrected by rotating the original because the staircase is circular, some will end up rotated in the opposite direction that they should be. Here’s the current situation:

I also tried using dupliverts, but the result is even stranger:

Anyone have other ideas/experience? Blend file is below:spiral_staircase_tilt.blend (120 KB)

Array modifier ?
spiral_staircase_tilt.blend (118 KB)

Yeah, that seems like the best way to go. For some reason I didn’t think of just using object-offset instead of trying to fit a spiral path. Thanks for the suggestion!