As a person who stitches just about everything I shoot, either nodal or tech camera, I would use the 280, what a great tool. The tech solution would be around a 20mm stitch on each side to get where you are trying to be and only a few of the best lenses will get there, (wides). You could easily do a multi-row stitch with a Schneider 60XL on your 280 and have a huge amount of resolution to work with. Pano ratio's tend to be 1:3 and you can get there with either of these with your 280.
Landscape is all I shoot and water is in about 85% of my work, water is so easy to stitch, it always blends. With the 280, you can find a nodal solution pretty quickly, and with landscape, it it's not exact, it really doesn't matter a the warp will get it together. I realize with a fixed architecture this is not as true as you are dealing with straight lines, and such. Single row CC will get it most of the time, multi-row Pt-Gui or Kolor's solution may do better. Nodal requires a level camera and your scenes may not work with this, but the tech solution would for sure as you are moving the back not the lens. I realize you don't have a tech camera but they are available for rental, and you should be able to also use your large format rig with the right adapters.
I started landscape stitching with a zork adapter in 2004 on my 1ds and have done it ever since, in an attempt to gain overall resolution without uprez.
With the 280, I would consider either a 55mm AF Mamiya or the newer LF lens, in the vertical orientation stitching across in verticals to gain a single landscape image. The main issue you will have with the 55 is pretty limited DOF, until you are at F11 or more. So you will need to check your images to makes sure you have a good hyperfocal range.
You could also use the 35mm AF, it's not stellar, and you will need to crop into the images as the edges will not be as sharp. However again at F11 and up it's an OK lens and will get the job done.