notice from the center cap out its black plastic, black rim, silver rim, rusted rim, silver rim. the clean silver is where you remove material from. you don't have to go all the way to the face of the rim either, just the width of the hub. its such a slight amount i can barely notice when i feel it. i was going to measure it with a micrometer for you but the battery was dead. you may need to remove just a slight amount from the angled section to make removal/install easy. post up if you have problems.
edit: i used a pneumatic dremel with a tapered bit. just something to remove a little bit of metal at a time.