Combining photo and life reference material

[Elizabeth Schott]

I understand all of those who will want to remain anonymous here, but I do need help.

I am in a situation where I am working on a portrait from life, but need to use reference for the background, because it was not in my studio. So I shot the model in front of the background then have to move him into my studio.

Well I have the hardest time with distortion while trying to size up objects. There must be a trick I am missing. I keep going back to Peggy