Offset.. can someone help me ?

Sorry, that is 1.5 hours. Site unseen by the new buyers who lived 900 miles away. I edited my post.

My SOB came with 2 different axles depending on rim choice. If you wanted wire wheels, the rear axle was 1.5 inches narrower. if you wanted steelies or rostyles, you rear axle was longer. A pic attached.

I work on my car from April to September. Last year I did most of the welding. We live in the land of rust and even though the car was put away in '86ish, it required a lot of work... not quite finished on body. This year I stripped a parts car (for bolts and missing parts) and rebuilt all the suspension, brakes, had the rad recored, went through my trans and discovered my engine (and my parts car engine) are boat anchors. Thinking it will take me 3 more years to complete and on the road. . When you are by yourself, work is slower.

Normally, my rostyle rim is has +24mm offset I want to use the offset to slide in a slighter wider rim using the offset rather than putting a spacer in place. What is the offset equivalent to the .75 ?

what-s-so-great-about-wire-wheels-anyway-1476933862079-640x628.jpg