For pots with smaller diameters under 115mm. I recommend setting the regulator top or bottom edge level with the burner jet holes. This will concentrate the flame toward the pot base, causing less heat to be wasted up the side walls of the pot.
The air intake holes of the Regulator are what governs the simmering options, Fully open to expose the center of the jets will quicken the boil. Reduce the air intake by lowering the Regulator, minimising the air flow to the jets, will give longer simmer times.
A few dummy runs at home will aid your set up in camp.
It is easier to leave the Regulator attached to the stove, it will still be stow-able in the provided leak-proof container. This also avoids additional space saving in your pot and less prone to damage or misplacement.