one scrap per file would seem to create a lot of unnecessary work and input/join statements.
You are right, Bruce, but:
to create such input/join statement is only a copy/paste of listing of directory from a spreadsheet table:
The same with joins.
With help of plain text editor you may simply create new th2 file just to save as the former one, rename scrap, delete all data exception "dividing line“ and save as new th2 file - see screenshot. You just must rename that dividing line too. With new scrap in map editor you just start from dividing line and after drawing walls you delete it. Etc., etc.
Martin