application as per your requirements...
Following Steps we will follow to standardize the document
1) We will scan each document to check if there are any contents in the region that we want to keep reserved
2) If we get any contents in this reserved section then we will analyse if we can empty the reserved section by shifting the contents with some offset
3) If shifting is possible and it standardizes the page then we will shift the content to make reserved section empty
4) If shifting of contents does not provide a expected result we will go for page content scaling
5) while scaling the page contents we will have to keep the aspect ratio as well as DPI and other properties of the page intact.