Changing htmltemplates table expression field

1.SQL type VARCHAR(4000bytes)→Change to TEXT type Is this possible? Is default 4000bytes?

2.Will this be supported?

・In dbdict, open htmltemplates table.
・In SQL table tab add following.
  Alias:m2
  Name:HTMLTEMPLATESSM2
  Type:sqlserver
・From field tab choose expression.
Change to TEXT from VARCHAR(4000) in SQL type.
Change SQL table to m2