Depends on the width of the wheels. From memory standard 7x15 bbs are et27, the wider you go the lower the offset needs to be to stop the inside of the wheel hitting the strut
Thanks Harry, how wide were the standard bbs rims , I was looking at some mono's with a width of 8 and et25. I just wanted to be sure they would be suitable for the arch, and not sit to far back or forward!!!