Get the term long call out of your head! That’s for AA pilots. Here at UA “Long Call” is a euphemism for RAP. You will be on SC the start of your reserve period until the end of it.
Example, I was on SC today for 2ish hours, they called to release me and put me back on SC the next day. Can you commute based on rolling SC? Idk, let you know as I experience it more.
They built more SC lines, in my base, tomorrow then they have reserves available. Got to make sure they got everyone!
I suspect I will never see 1000L release on last day of long call going into HDO.
YMMV