[dev] Customer with multiple IDs, too much IDs

We have a lot of customers and we implemented the function "Customer with multiple IDs" described here http://doc.otrs.org/2.4/en/html/x1801.html We have a database backend for customer users. The problem is that we need to assign a lot of customer ids to a customer user and the textbox is too short. I need to insert more or less 600 characters in the CustomerIDs textbox. The "customer_ids" row in the "customer_user" table is a VARCHAR (250). My idea is to change the VARCHAR (250) to VARCHAR (1000) so I can insert a longer string. Is this a good idea? Can this modification create problems or have unforseen consequences? Do you have any suggestion? Thanks, Alessandro Cortiana