Seatpost (clamp, actually) with ample tilt...?

[OakLeaf]

Shoot, that post is too skinny. I believe my bike requires a 36.1mm wide post (I'd have to double-check, but that's what sticks out in my head). Otherwise that looks like a good solution.

Shimming the clamp is a thought. I'd never considered that, but it seems like a workable solution. I wonder if that could damage the rails, though...?

It might be worth looking at the new ones, I think there's still some back tilt available, just not as much. They come in 31.6 now.