Even on wheel steered boats the perch seats aren't very good for steering from, unless you have an ap remote or one of those new wheel steering extenders (like a tiller extender but tied onto a wheel spoke - invented, IIRC, by a repsondent here and sold to Davis or Forespar - a neat idea).
The main advantage is a great seat for crew. I use ours primarily when sailing downwind or motoring home.
May be hard to do with only a single pushpit rail, although IIRC there was a thread here within the past six months about doing that.