Old Tire Size Conversion?

I just got two new aluminum slot wheels, so I have a matching set at all four corners

14" wheels

Here is what came with the car (1970 Duster):

Rear: G50-14

Front: GR70-14 / 205SR-14

GR70-14 were on two tires in the trunk, I assume a matching size for the rear

What do these convert to, in modern sizes?

I did a quick Google search for the G50-14 and they are like $310 each!

What is a modern tire size equivalent?

Does this make sense:

G70-14:
235/60-14
205/70-14
205/80-14

What about the G50-14?