I have the same size tires on my 72 Duster.
15x6 front and 15x8 rear with 4.5 backspace.
I am going to switch to 205/65r15 on the front. They are V rated for a stiffer sidewall. Hopefully I won't lose any handling with the narrower tire. I am hoping the skinnier tire will turn with a little less effort at low speeds with my manual steering. It is livable as is but I want to see if I notice a difference.