The focal length only determines the number of tiles for a given field of view, and thus the resollution per tile. Perspective is determined by your shooting position.
Yeah. I am generally shooting to make prints around 24"x40" at 300 dpi. That ends up being around two rows of five to seven images shot in portrait orientation on my cropped sensor camera.
Depending on the overlap, with a 17mm lens that is well over 200 degrees of rotation--with the distortion of that wide a field of view, it would not be ideal for realistic rectilinear panoramic prints. It is just too wide in the print size I am targeting.
At 24mm it would still be near 180 degrees...very wide for every day panoramic work.
45mm, on the other hand gets more around a 90 or 100 degree field of view with six or seven portrait frames.
With the 45mm lens I can always go wider by shooting more frames. I can't do the same with the wide angle versions.
The 90mm looks intriguing. I see that it has very high IQ, but all these lenses are at least quite good, so I figure for my first foray into TS, 45mm seems the best middle-ground (at $1,200 I don't want to call it a compromise).