Don't think this is a valid way to go about it because to be frank I can't tell the difference in image quality or look between any of the 50/80/150/250 lenses I use. The longer the lens the more likely it is that you might benefit from buying PS rather than S (according to the chief repair guy at Bronicas European distributors anyway.

I'd avoid the S teleconverters but apart from that there's no real sustitute for deciding what focal length you'd use most.