The best way to check for clearance in the arch is to take the spring off the coilover, and jack up the suspension through full travel of the shock.

I've got a solid axle in my rear and it was suprising how much clearance I needed with one side up and the other down.

I've got RS wheels but in a standard Focus shell, its a close fit, but it does clear.

I've spent hours on the stupid little things, they just go on forever, you do one thing and that affects something else.

I'm trying to get brake lines onto the axle at the moment.