Now that you ask, I guess height isn't really an issue. It's more about grade. Height becomes an more of an issue when the grade isn't ideal (e.g. if you have to go up an
extremely steep hill that has the engine working way outside its minimal BSFC zone, you want it to be a short climb
).
I wonder what's the "ideal" hill profile...
EG for the downgrade, it seems like you'd want something that goes on as long as possible with a terminal coasting velocity of roughly 40-45 MPH (so you're not burning up too much kinetic energy on wind resistance).