8-3/4” axle conversion

I need to swap out my rear axles from the 5x4 to the 5x4.5 on my 8-3/4. I thought it would be easy but I get more confused every time I reach out to a manufacturer. I understand that the offsets are different and was told I need to change the backing plates as well. I asked Dr. Diff but he did not have the backing plates for the axle package he had to convert me over. I hope I am just overcomplicating this and someone can simplify it for me. Can someone enlighten me? I am not the one doing the work and I was hoping to stay closer to stock rather than throwing on something like the Wilwood aftermarket. Any insight would be appreciated