What do you mean by "field in SQL command translated to Varchar(8000)?". Which SQL command? Aurelius doesn't create any field with size 8000. What it does when you don't specify the size of db column is to use the default value in global config, which is 255 by default, not 8000. Unless you have changed it.
About Text field, yes, that is by default, it's considered as a blob by Aurelius.