For a smoother you do not need a jig or a number. Finger pressure gets you there and it is what most people actually do.
Sharpen normally, then on your finishing stone take a few strokes with extra pressure on one corner of the iron, then the same on the other, then a few in the middle. More strokes at the corners removes slightly more metal there, and that is your camber. Ten extra strokes each side is a good starting point.
Test it before you go further: hold the iron up against a straight edge and look at the light. You want a barely visible crescent. If you can obviously see a curve, that is too much for a smoother.
The better test is the shaving. A correctly cambered smoother produces a shaving thinner at the edges than in the middle, and it will be narrower than the iron. If your shaving is full width with square edges, you still have no camber. If the shaving is much narrower than the iron, you have overdone it and you are now taking many more passes than you need.
If you use a honing guide, the same trick works — pressure at the corners while the guide holds the angle. Some guides have a wheel narrow enough to let you rock slightly, which does it faster.
Easing the corners alone is not quite the same thing, but for a first attempt it removes most of the track lines and it is very hard to get wrong.