Generally a small dome can work quite well, particularly for CF/WA as you stated. You do have to stop down to f/8 or higher. While it's never going to have the image quality in the corners of the shots that the large domes have, results can be quite good.
Larger domes are better overall, but work particularly better at more wide open apertures, and excel at over & unders, something that small domes don't do well at all.
There is also medium-sized domes such as the Zen 170mm, which offer a very good compromise, as they are a section of the larger 8.5" curvature of the larger domes. They still work better stopped down, and aren't quite as good as a larger doem for over & unders though. But they offer the ability to do quite good CF/WA, particularly with FE lenses.