Standing rigging is the stuff that holds up the mast. It is the permanently secured rigging. In the Omega there are two shrouds (one on either side of the mast) and a forestay (or jibstay). When you step (put up) the mast you should set the tension on all of these just tight enough so the mast won’t flail around every time you go over a wave. If the mast is “banging” violently it is shock-loading the standing rigging and eventually it will fail.
the mast should be vertical (90 degrees from the horizon or to the seats) and not bent. Because the shrouds and stay join the mast at approximately the same place mast-bend is not a factor here. Of course the mast should be centered and straight from side to side too. By leveling the boat and putting a small weight on a halyard you should be able to tell when the mast is vertical (fore and aft as well as right and left). This is just a starting point and it can get very technical from here depending on the cut of your jib, sea and wind conditions you will be contending with. But one setting of the standing rig should cover you for a wide variety of conditions, and as I said, I’m trying to keep this simple.
The jib halyard is used to raise the jib and as you tension the jib halyard you will notice that it takes some tension off of the forestay. So the jib and the jib halyard are now supporting the mast in opposition to the shrouds because the shrouds are anchored somewhat aft of the mast.
When the main is up and you pull hard on the main sheet going to weather or when you have the boom vang on hard you are also putting additional tension on the forestay. These are things you should understand, but since I’m trying to get to the down and dirty hints for trimming sail when under way I will let you read more about that some winter evening when you can’t go sailing.