Ideally you want 1 report which does both, especially if it's just a "sizing" thing. It's a bit of hand-code to change the landscape property, then adjust all the size properties, and column widths, but at least you only have 1 report to maintain.
If the 2 reports are different, ie have different columns, then I would probably use a normal Clarion Source procedure (let's call this the "report") which takes the p_web parameter. Then some decision code in here to select which one of 2 report procedures (passing p_web onto them.)
cheers
Bruce