My only question is .... add coals after an hour. When does that begin? Seeing as Weber says to let the coals sit for 30 minutes to ash over. So is it one hour after the light or one hour after they ash over. I’ve always been confused on that.
You add the coals 1 hour after you put the bird on. If your using a Weber chimney, your briquettes should be ready to dump in your baskets, roughly 15 minutes after lighting. If your waiting for them to be all gray, your waiting to long to dump them. About 10 minutes after lighting them, shake the chimney like a chef flip/shakes a frying pan. May take a little while to get the hang of it but it redistributes the lit coals and speeds up the lighting of all the briquettes. They don't have to be totally all gray, just partially. They will continue to light while heating your kettle.
This is also recommended by Weber - After dumping your coals in the baskets, put your cooking grate on, then the lid and preheat your kettle for 10 minutes before putting any food on.
In that 1980's Owners manual that
@Mike in Roseville posted, Weber says to figure 11 minutes per pound when cooking a turkey(unstuffed). I know because that is my manual depicted in that photo. Using that formula, your bird should be done in 132 minutes. I would recommend checking the breast meat at 1 hour and 50 minutes. You can always cook longer if needed but you can't take off temperature. As
@HoosierKettle recommended, pull the bird as close to 157 degrees as you can. Then let it rest for at least 30 minutes before carving.