I have 18" wheels on my '49 and mini-tubs in the back to allow a bigger tire in the rear. Mine are American Racing 'Boss' wheels. I had a shop in Phoenix machine the mounting face to get the offset exactly where I wanted it. Here's a link to a photo

https://talk.classicparts.com/media/bath-1.7192/

I used the worksheet on the Wheel Smith's website to see what would fit.

https://thewheelsmith.net/wp-content/uploads/2021/05/Wheel-Fitment-Article.pdf