As with all callmakers each has their own idea of how to make their calls, I too, fall under this shadow, I use changeable chucks to turn my pots on one lathe. I drill my sound ports after I turn the pot. I use an 1/4" gouge to cleanout my inside until I get ready to make my pedestal then I go to my 3/32" parting tool. Having the ability to change out jaws on a four jaw chuck gives me such an adavantage, as my calls may be single or dual purpose, this works out a lot better for me then a face plate.
Concerning a video or tutorial in turning pot calls, you will be best to do a search and go from there.