I don't know...
What is correct?
Pure power? Control?
As said, several top ATP pros landed on their service side foot, the right. They pivoted off their left to get the power.
Some guys, like Roddick, tend to stomach crunch to get some of their power.
We are NOT all the same!
Post vid. If your serve is strong enough for your size, it's good enough. If it's weak or inconsistent, time for a change.