Peter in Selkirk, Manitoba is trying to fit his countertop flush to a wall that is not perfectly flat.
If you look closely at the back splash part of formed countertops you will notice that they have an "L" shaped lip right up on top. This gives a bit of a hollow space behind the back splash. You can actually cut away a little of the overhang on this top edge and push the counter top back flush with the wall.
In the photo you see a compass set to the largest gap from the wall, scribing along the top of the backslash. Follow that line with a jigsaw and the counter will fit the wall like a glove.
Tip: Check out new "down cutting" jig saw blades. They will not chip the top of the plastic laminate when cutting with a jig saw.