I just turn it an 1/8th or so every few minutes. When the outside husk is burned (black) I turn again. After a full rotation it is done. Honestly, I have never over nor undercooked it.
My wife poined out that some flecks of burned husk end up on the peeled back ear. I am not bothered by it. Adds to the overall end products imo.
Mexican corn, known as “elotes” on the cob and “esquites” cut off the cob and served in a cup. Unfortunately down here they use field corn, or at least it seems like it to me. (I also was a production corn farmer.)
Mayonaise, lime juice, Tajiin and most of all, Cotija cheese sprinkles. Shitty corn or not, I still love it.