Hello Zebras

I'm looking for advice
Almost entire referee life I've been working 5-man crew, mainly BJ but every once in a while (playoffs e.g.) I get BJ@7-man and it seems to cause some problems how switch to new crew size
Main problem for me is that after covering from sideline to sideline I have to focus on the middle of the field - is there any way to do it correctly - cover my zone (middle of the field) and not let guys go behind me near the sideline?
Will be grateful for any advice, thanks