I bring my temp to 155 and then, yes, I fiddle with the knobs until it is holding a constant temp. Then I place my grains and make any heat adjustments needed to get back to 155. You'll find that after a few brews you will know where to set your burners.
Just an FYI, whichever method you use, do not allow the water to get above 170 as this may result in tannin extraction and off flavors.
And now we go AG!
On Tap: Nadda
Planning: Extra Special Bitter