I wouldn't be buying any lenses for this format until camera is in your hands... It is a long format that only one lens FL will normally be used with... With long formats, there is a height to width ratio to work with where there is a reasonable usuable vertical height that is a little limited, so you take what you can work with...

BTW FWIW, I shoot a 5X12 Al-Vista panoramic camera that gives sufficient height, but stretches width, but can't imagine any other FL on it...

Get camera and one lens on it first and test...

Steve K