I've always put in an amount when using their online form. In my experience, and that of some other folks on the board, if you are eligible for a CLI, they will give you the higher amount of what you are qualified for or what you request. I've never gone nuts with my requests, but my strategy with BoA is to aim high and know that they'll give you whatever max they're willing to give even if you over-request.
That'll help in the future anyway, but when you call them, I'd just pick a number and a reason and see what happens.
