Hi mmarty1,
no need to worry about boiling liquid, unless you just like to see that 212F.
However, I've read a few good books and some seemingly knowledgeable people on this forum state that a "roiling boil" is better than "barely boiling".
disclaimer: On my electric brew system, I do have a PID controller and temp probe, but it is operating in a "duty cycle" mode. So my heating element is at 100% duty cycle, (full on) to heat wort quick as possible. As the temp nears 212, I gradually reduce the duty cycle, ending up at around 60-68% to maintain boil. when I was using gas heat, I simply kept an eye on it and slowly lowered the flame as it began to boil.
And I never forgot to keep an eye on it...ever...I never got distracted by a conversation or football game, and got snapped back to reality by the sound of precious wort bubbling angrily about the cauldron like golden malten lava, and sizzling onto the garage floor into a sticky, semi-caramelized layer of fleeting regret ....not I.
Cheers