I've used the FSA K-force SB25 on all of my bikes for over 10 years. They work great and you can also get a 32mm setback model. It has a 2-bolt rocker style clamp that permits very small changes to the saddle angle. I always shop around to find a source that's selling for far less than MSRP.

The normal setback for most posts is 20-25mm. Needing a 25-32mm setback has nothing to do with a frame being too small. Smaller frames are often made with steeper seat tube angles that may require more setback on the post. The saddle rails also play a part in the need for a post with more setback.