The programs in WordSmith Tools can handle virtually unlimited amounts of text. They can read text from CD-ROMs, so giving access to corpora containing many millions of words. In practice, the limits are reached by a) storage and b) patience.
You can have as many copies of each Tool running at any one time as you like. Each one allows you to work on one set of data.
Tags to ignore or ones containing an asterisk can span up to 1,000 characters.
Press F9 to see the "About" box -- it shows the version date and how much memory you have available. If you have too little memory left, try a) closing down some applications, b) closing WordSmithTools and re-entering.
See also: Specific Limitations of each Tool