Guys, they are only detuning to learn one song so changing strings is not a preferred option.
But they are right in that looser strings wobble a LOT more which means more buzz even with added neck relief. And drop C with string gauges suited to standard E is gonna be difficult to avoid buzz. You may have to live with some amount of buzz so be prepared for that.
So, the good news is that truss rod adjustment is a simple and reversible way to go. Just remember how much adjustment you needed to when tuning down and reverse the adjustment the same amount when tuning back up.

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