About SxS guns blocking the view, I'll vote "yes." I shoot trap doubles with both SxS and O/U guns and at rising birds you can't be as quick with the SxS. On some stations (e.g. 2 and 4) you just have to let the bird appear over the top of the barrels before going to target.

That said, there were a lot of good shooters back when, like Phil Miller, Ned Lilley, and John Sternberger, to name a few, who thought doubles worked just fine.