It's set so you can connect between 8-9 for example and run the program for different hours.

HOWEVER, it's a hassle, since it FORCES you to connect at whatever times you set, even if you want to do something at some other time...
There's no time differential for weekends either. You have to connect at that time, and THEN you can change it. Yuk.

Don't mess with it. LEAVE EVERYTHING at 24 hours.

I have one machine on a separate phone line set to autoconnect and send in a result whenever it finishes. That's the simplest way.

Run a few workunits on your own first to see what they normally do, and then go farther if you want to do more advanced stuff.

There's a great 3rd party package called UDMonitor that is better suited for managing your workunits. You can download 10 in sequence and run them all before calling in....or decide yourself to send in some results when you see that they are complete. I usually do that myself once or twice per day at the same times. It keeps the phone lines open the rest of the time.

Once you install it, there's a wrinkle here. Start it with the WCG bat you see in the UDMonitor directory you set up for it. The default is grid.org, which will cause problems here. Keep UDMonitors separate for each DC project. You can't mix and match in the same one.

UDMonitor is a bit complicated when you first try to use it. There may be some more threads around here that talk about experience with it. It works for me.

Some folks on the http://grid.org forum have had EXTENSIVE experience with UDMonitor. Look at the UDMonitor thread in member-to-member support, even if you are not crunching for them. The workings of UDMonitor will be the same.

I'll point you to the first page, because it has a link to the UDMonitor website.

UD Monitor - download several workunits at once