For passenger work diagrams are generally made up of Monday to Friday, Saturday and Sunday work. (SX, SO, Su). In my experience it has never been the case for SX diagrams to be different just to fit in a different link on different days.
Night diagrams however can be different, as they work into the following day, so a Monday to Thursday (FSX) night diagram is usually different to a Friday (FO) night diagram, because the requirements of a Tuesday to Friday morning are usually different to that of a Saturday morning.
Hope that kinda makes sense.
Driver / Conductor managers usually manage around 25 staff each, although that is an approximate figure. The crew they manage could be in different links.
The biggest link I have seen is at Chingford, around 112 lines in the roster, takes over two years to work round. They make it work, you just need a big sheet of paper to hang the roster.