I know you said 18-20 and I do not know of any 8 lug steelies in those sizes, however, there is a guy named Steven Dillman who can get you a set made in 22". He has quite a few sets of the 22x9 GM Transit wheels, and he has a machinist who can modify them to any bolt pattern, backspacing, or width that you want. I think it's $1300/set for the 8 lug 22x9s. I got my Transit wheels through him and hes a good guy to work with. We communicated through Instagram, but if you don't have Instagram I can try to get his contact info for you. He might be able to help you out with sourcing some 18s or 20s if that's what you prefer.