Back spacing for my new wheels? any help and or pictures would be appreciated thank you

BBOE said
I have 60r/255-15 on the rear of my 70 Duster want to put 15by7 on the front need to get the back spacing right want the outer edge of the front tire just inside the fender well any help and or pictures would be appreciated thank you also the 15 x 7 on the front would be a 60 R/235by 15

i have the same set up i did 15x8 255 60 15 in the rear but in the front i have the later big bolt disc brakes i went with 15x6 255 60 15 4.50 back spacing i use to have 15x8 but god damn no power steering was hard to turn. the later disc stick out the tires 3/4 on each side 4.25 was not enough for me