While looking through the SQLite database scheme I found two things which could be removed by my opinion.
First thing is the size value of fields. SQLite totally ignores them. I can understand that it was kept for consistency, but it just makes the scheme bigger for SQLite.
The second thing, which I would need to check again is the INTEGER PRIMARY KEY NOT NULL thing. As far as I'm aware of, if you define an integer primary key, then you don't need to write >NOT NULL< as SQLite will not allow to insert an empty value into it because of the primary key constraint. (Except if you insert a row with NULL as the primary key value it will get the highest available row number + 1.)