You can choose between the option to run SETI only when your screensaver is on, but u can also choose to run SETI always. To crunch more WU's at the same time I suggest u download SETIdriver. with that program u can buffer WU (in case the server of seti is down) and u can crunch more than one WU's at the same time. this program allows u to completely control your crunching, it's great! with that, everything u asked is possible. happy crunching!