Hi - I did not use match photo but imported it as an image. Actually I did what I needed to do for the client in photoshop and now re-doing it in SU to practice. I thought this is a good house to learn on. I did not think of scaling the porch since the house was scaled. I guess any part of the house that is not flat with the siding such as the eaves and porch will need separate scaling. If I had an angled photo and used match photo, would that solve the problem? I would think that accurate scaling would be a problem with an angled photo too.

Make the lattice into a component or group and place it where you need it in the model. Remember you're working in 3D space so you can place one thing in from of another.