I'm still looking for advice on tires and asked at the Chevrolet Forum too. Do the sizes I posted in this thread fit the car without modification to the car? I'm cross-checking beyond reading what's on Automobile-catalog.
I do see this is a popular car model for putting large rims on.
As for news on Boxy, We have a trickle-charger on it now which is a nice aid; I started the car on the first crank and I only pumped the gas three times before I cranked it. I removed the mud-flaps too.