Sorry for the "Welcome" lol. I welcomed another user just before you and I think I still had that in my head

But belated welcome anyway haha.
But yes, if you plan on having your unit run for long periods of time, torture tests will let you see how your unit does "under pressure" so to speak.
A torture test isn't going to find problems really. It will just show you how hot your components get when you stress them. Usually, if you suffer from overheating problems, running Prime95 for just a short while will get your components nice and hot (normally a few hours is more than enough time to tell if you have a problem). But in your case, letting it go for a full day will show you how your unit will do over a long period of use.
The Everest version that has the nice torture test is the "Ultimate Engineer Edition." Each component you test has it's own temperature meter, which is a really nice feature. If you use that test, just note down what the temperatures are at, then look online for acceptable temps. If they are too high, then you'll know you need better cooling. If you find your computer turned off at some point, then you know something overheated and you definitely want to get some better cooling.
As far as the Quad core thing...I'm pretty sure you just need one Window open. If any of the cores overheat, it will cause your computer to shut down. If one of your cores has a problem, Prime95 (or any torture test I know of) will not tell you which core is bad. One open Prime95 or Everest window should get the
CPU nice and hot.
