Yes, you have to open the slot up with a small bit or small drum sander, which is what I used. The pants are supposed to set against the gear. When you get the slot opened, stick something of the right size between the rear / bottom of the wheel pant and the bench. I used a piece of slotted landing gear stock. This will get the pant at the correct angle (your preference) on both wheel pants, and using the brace will make drilling the pilot hole a little less of an event.

JW