help required urgently

[thebluepearl]

The ride isn't that bad but as said above I was planning on fitting 17" atlantis wheels from the 206 but now have stumbled on the fact I'm a lot lower than I wanted to be, I've had a look at the rims and on the backs they say 7jx17-28 so somehow need to work out the correct spacing to fit the 306 I went ahead and bought 15mm front and 20mm rear spacers but now believe they will be too far out the arch?? To fit on the lowered puf