i have 245 40 18 on the rear and 215 40 18 on the front and they fit perfect!! (now)So the car is a Gold with a 4.10 ring and pinion? No wonder the speedometer is inaccurate, you need a 2.5 cluster with a 4.10.
Just use 205 45 16. You will have the least problems. The 205 50 16 are a little tall and you want to raise the car too?
Yes you can use 205 on 7.5J wheels. I think 225 40 16 would be better but is almost nonexistent now. You might have some clearance issues. It all depends on the car. Trust me!