By any chance can you share who made your wheel in 4 1/8 backspace? Cuz I contacted eheel vintiques and said they had to set wheel outer barrel reverse to get any more than 4.25 backspace. However, doing this no longer able to use trim rings!:(
Specialty wheels made them for me but coker tire bought specialty wheels and they no longer make specialty wheels stuff. You should be ok at 4.25. They do not have to flip the rim. It will be right on the edge.