Using some different struts, you'll find the tire offset required does differ.

But probably not by the amount you are talking about.

15-20mm ET is the maximum that will fit under a 1200 without flares etc. It sounds like yours are 35ET or maybe 42ET.
ET acronym means "pushed in" in german.
Can you measure yours?? and let us know.

Measure the width and then measure from the back of the rim to the mounting face on the wheel..I'll do the simple maths and tell you what you have. That will give us the numbers to suggest a possible strut solution.

It might be that you do have the wrong wheels and will need to get new ones.

All the best.
Chris

ps. I'm having the same trouble with getting wheels and tires for my car. I'll probably end up with Simmons, because they can manufacture exactly what you need, it takes 6 weeks though.