field screens and upgrading customizations from3.1

I am planning the upgrade to 3.2.1, and reading up on field screens. Part of the upgrade task is to re-do changes I had to make in the source code where necessary. Two of the changes were in edit_fields.jsp and create_fields.jsp, where I had to change the number of lines/rows for environment from 2 to 1 and for description from 20 to 6. I cannot see in the new 3.2 based field schemes how I would accomplish that in the front end. If I can, how? If I can't, what files would I need to again modify to make thse changes?

Thanks