It's sometimes the simplest foods that give us the most trouble. Many years ago, I lived in SF, CA and one day on the way out of Napa Valley, I bought fresh corn at a roadside stand. It has to go down as some of the most memorable corn I have eaten.
I have since replicated the tenderness and the crispness I associate with good corn. I have also come to recognize, it's not corn that is tough but the way in which it's cooked makes it tough. Not knowing what went well that time, years later, I began to time the cooking of my corn. Feeling I was doing something wrong, I increased the time each time with each cooking though it was tough each time. After going from 8 to 12, then 15, and even up to 20 minutes to no avail, finally I had the good sense to do an about face and cook it for about 3-4 minutes and voila! That was it!! It doesn't take long to cook corn. The smaller the kernels (not the ear) the more quickly it will take. If you stand and watch it cook, you can actually see it take on a slightly different color and appearance and soon will recognize when it's done. I highly recommend that when the barbequed meat is resting, that you then begin cooking the corn without getting distracted, meticulously tend to cooking the corn and at 50 cents an ear, you don't want to mess it up.
Not that I recall a corn shortage in my life until last year's drought, but I admit, I even bought corn with slightly dry husks for my summer barbeque. So long as it's not moldy, fresh corn will always cook to a perfection.
When looking for corn, I don't open each one. I go by the weight of it in my hand and I select the heavier ears.
For me I simply add butter and salt and have little reason nor incentive to do something otherwise. Hopefully with the help of my trials, you will have perfect corn, too!! Let me know!