Foating Ball vs. Trunnion Mounted Ball Valve for Pigging Service

Please, I've an need for the forums consensus on the following:

1: Would anybody care to comment on the industry accepted reccommended practice for the deployment of Floating versus Trunnion Mounted Ball valves on pipelines for pigging service? Which is prefered (floating ball or trunnion mounted).

2: Do the maximum operating pressure and/or fluid medium (gas or liquid hydrocarbon) take precedence over the application (pigging) in selecting the appropriate closure member for Shut-Down Valve located on a piggable departing / incoming pipeline?

Thanks in anticipation of receiving your views.