Practical experience here, my friend Jim had his amazon wheels widened from 4 to 6 inchs by putting an extra 2 inchs on the outside,looked great, with 195/60 tyres it drove like a go cart, lots of bump steer, great in the corners, hopeless on the straight. We put the 5 inch wheels, widened 1 inch on the outside from my PV on it and it was fine, interesting I had some 4 inch wheels widened to 5-1/2 inches ( all on the outside ) for a 121 wagon with 185 -15 tyres and it was fine. So it may have been the tyres or the suspension or there is a fine line between 1-1/2 and 2 inchs extra offset. We both have 6 inch rims with P24 ( one inch extra outside and inside ) offset on our amazon sedans and this is perfect,
Hans