The air crew still work 24 hr shift. On First standby the shift hand over is at 0920 (depending on squadron) and you remain on 1st's until 0920 the following morning. You then revert to 2nds where you are on 60min notice to fly until ECT. The SARF ideal is a run of 3 shifts (so in effect 6 days) but runs of 4 are common (if pushed, 'broken' runs of 5 can happen, ie. a run of 3,one day off, run of 2). As for time off, it depends on your shift planner and on how undermanned your flight is. If there is the flex, you are likley to get 1 weekend clear a month, but in a month there should be a period where you will get 3 days off in a row-not likley over a weekend. In short, there is a fair amount of stand down, but none of it is really plannable. you will get time off at very short notice (not often) and be called in when 'off shift' at the very very last moment(often!!)
That being said, the job is fantastic and I wouldn't change it for the world. Good, challenging flying and a LOT of job satisfaction!!!
Hope that helps...
NV