I’ve been in so many meetings endlessly searching for the Best Day for on-call shifts to start/end, and feel I have heard it all at this point, every day of the week seems to have pros and cons. Current team just does Monday, because that’s when the week usually starts, and I really don’t want to talk about it anymore lol. If it conflicts with one of the abysmally few US holidays, adjust accordingly, you’re a bunch of smart clever adults, you’ll figure it out.