I think with tell boxes you are gonna be screwed... as they are "new" boxes every time, and will use default settings. But I am just guessing here, I do not use tell boxes.
I personally have a window that all incoming chat goes to and leave it at that. (then seperate one for melee/spell, and seperate one fore random/environmental, ect) I do not generally have an issue following along with chats that are all funneled to the same window. And being a "permanent' window, the settings stick.