What rims/tires will fit a stock-like application?

[Christians Fleetside]

My son and I just started working on a 1958 Chevy Fleetside that had been sitting in the Arizona desert for 40 years. It has some ridiculous 10" wide rims in the rear and 7" inch in the front. We are on a tight budget and we want to make the truck close to stock. Just to get it rolling I want to put the 7" rims in the back and get a couple steel rims for the front that would be close to stock.
1) What is the stock rim size for a 1958 3200(six bolt)? The spare appears to be around 15" x 7"
2) Is there a match from a later model car or truck that would fit?
3) What was the stock tire size? The spare tire says 8.45-15 and has a diameter of about 28 inches
Thanks in advance
Paul