The problem with tray searching is that of volume. I will go to many banks and they don't have any halves at all. With boxes you at least have a lot of coins to sort through. The problem with a box is that you then have a lot of coins to dump. I have not done a box yet myself, but I do have one on order I hope to pick up next week.
What I did was to start with trays and also ask for rolls. You should get a feeling about which banks are hit up by other CRHers, and some tellers might offer to order a box for you without you having to even ask. Once you have identified a good dump bank or three then start with boxes and see how they perform.
HH
