Hi, I know this is an old post, but I found a solution I thought I would share. I am also working on an older home with 21"Tck stone walls. Here is what I did:
- Went into the door Specifications (Double clicked on door)
- General Tab - Set my door size to 42"W x 83"H - This is the pre-existing rough opening size in the wall.
- Options Tab - Checked "Swing Both Ways"
- Casing Tab - Turned off Interior and Exterior casing
- Jamb Tab - Turned on "Door Size Includes Jamb"
- Same Jamb Tab - Set jamb width and height to 3" which gave me a 36" x 80"Door, Unchecked "Fit Jamb to Wall", Set Jamb depth at 6" and Inset to 7".
Not perfect, but close! And the same concept applies to windows!