Rethinking My Brakes, What Fits?

[Richie-Van-GTi 71 2 Cars]

After some messing about I can make the CL500 brembo's fit my hubs with 305mm discs but they are damn close to fowling the lower wishbone on full lock and the fabrication would be a bit of a nightmare. Decided to just get the 406 brembo's for now so ordered a set of them and some drilled and grooved 288 x 28 discs for a xantia. I am hoping to stick to 15's, in particular the c5 alloy/steelies for reduced unsprung mass and cost of tyres. Anyone tried this combo and know what the fitment is like? Guessing spacers required but do they fit inside the rim?