If you are going to use corn syrup, use light. I use corn syrup, honey, and some molasses, to equal the amount of whichever one you might use alone. I also add some cherry preserves, just enough to get a faint hint of cherry. I don't have measurements, because I don't measure, just keep adding stuff until it tastes right.
I also don't cook it, just mix it up with a stick blender.