OK, I solved this by normalizing the landscapes so that the overall dimensions of each landscape are identical. At some point I will try to do the mathematical fix and figure out the best way to adjust the fill x and y.
Thanks @nick_sherman, @davebollinger, @sgs for the tips. While the answer involved a more base problem that I had failed to identify, I learned some new tricks from playing around with your suggestions. Now I have several answers to problems that don’t exist for me. . . yet! 
