First:
The "viewable area" you refer to relies solely on the capture device used. Some capture cards clip more off the sides than others. I know that with my Winfast TV2000 XP card I am able to hack the settings and set my own clipping range, but most (none that I know) other capture devices don't have this ability.
Second:
Both TR47/Cowclops transfers have the original PCM audio off the LDs.
Third:
The advantage of an anamorphic transfer relies solely on the screen you view it on. Widescreen TVs benefit the most, as the anamorphic widescreen format was designed with them in mind. Standard analog 4:3 televisions will actually lose quality when showing an anamorphic image, as lines are actually clipped to scale the image down to size. Would a standard letterbox transfer look better on a widescreen monitor than an anamorphic? That's debatable. What it really comes down to is which one can upscale the image better -- your television on a letterbox transfer, or the software used to upscale an anamorphic transfer during the editing process. Usually an anamorphic image will look better simply because most televisions can't upscale an image nearly as well as video software can. And don't forget that a television has to upscale at real time, which makes a huge difference.
Lastly:
If you don't have a widescreen television, you should consider a letterbox transfer such as either TR47/Cowclops v1.0 which has digital PCM sound, or the EditDroid transfer which in my opinion has a slightly better picture but no PCM sound. Both are excellent transfers though.
Newer transfers such as Citizen's releases are done on dual-layer media with a substantial increase in quality. Citizen's PAL DL transfer of ANH is my current favorite.