This is a very good tutorial. The biggest reason to shoot horizontal panos with the camera vertical (and vice versa) is to keep the resolution as high as possible. At least that's why I do it.
Other than resolution and DOF, there is really no advantage to using a 50mm lens rather than a wide angle or ultra wide angle. My experience is that it's generally best to use your widest focal length, including with zooms.
great simple tutorial on panoramics. i have done a few now and am happy with the results. CoUld you tell me the advantage of shooting in portrait mode rather than the usual landscape mode>?? thanks don