I ordered light rail matching our existing cabinet and I’m undecided about how to go about installing it. The light rail sits square under the cabinet with a little lip, and that works fine on the front side of the cabinet. However, on the sides, it doesn’t sit flush with the siding since the front side is a little wider. I hope the pictures explain better than I can.

I can think of two ways of installing it: install flush with the front side and fill in the gap with a yet-to-be-purchased filler, or chisel a little bit of the front side such that the light rail moulding sits flush with the side.

Any other ideas or tips I might not have thought of?

Thanks