I had to expidiate this issue. Here was tech support answer:
"You can change the column varchar(xxx) number, but it will be unsupported. Also during a DB upgrade it may change the value back or fail, since it is not at varchar(100). The best solution is to submit a feature request"
Here is what I did:
I set it to varchar(250) and created a document in my ORION UPGRADE folder on the server with a FYI to set it back to varchar(100) before any update and to change back to varchar(250) after updates. Not a big deal because we are sweeping this table to a historical reporting DB (compliance related).
I also opened a feature request to add a field in the syslog setting to allow this column to be defined by the customer.