Long call reserve is a friggin joke at UAL. That is because they can convert you to short call 7 times a month and they do whether there is a reason for it or not! It doesn't seem to have anything to do with coverage or open flying.
For instance today they had 5 short call reserve guys on the hook in LAX and not one open trip.
In all fairness after 4 short call conversions they are supposed to hit somebody else if they are available.
I was home based years ago when I flew for ATI. It worked pretty darn well.