Hello: I bought a pre hung door and have some questions in regards to the same.
1. The new door frame is 4 5/8 but the width from "drywall - stud - drywall" is 3 5/8 - the width of new door frame is 1' more. Do you get a door frame with 3 5/8 or the 4 5/8 is the normal size? If so do I have to saw the frame by 1'?
2. The gap for the door opening is 26 3/4 where as the new door is 25 1/2. Do you insert a piece if wood say 1" on one side from top to bottom and leave spaces for shims on sides? Is that the right approach?
I have nearly finished the bathroom renovation and this is the last major challange I have.

Thanks for all your help.