What about getting some 20mm ply and cut a disc and hold it up to your wheel and see how it looks / moves? If you pop the spring out you may be able to jack the wheel up and see if it touches? Front may be easier to do.

On mu 205 we have similar issues and one thing we are considering is putting the alloy on a big lathe or milling machine and taking 5mm off the back of the wheel as it is quite thick at that point, this will bring the wheel in 5mm. You might gain 1 or 2 mm on the PCD adapter too but obviously it needs to be safe.

You may then try thinner outer lips if that works?