Coolant Overflow Tank/Reservoir

From the suggestions of some, I found and bought a Hyundai Tiburon/Elantra coolant overflow tank and mounting bracket

It's going to be way too tall and I need to find something else that will work

I would like to have it mounted on the passenger side of the radiator/inner fender area

How many ounces does it actually need to hold? There are a billion options for tanks

1970 Duster with a 440

Suggestions?