Hi Craig, I'd say between two to three and a half hours.
My suggestion is to work backward from your serving time and allow at least an hour for resting. If it gets done early, pull it off, rest it and hold it. and if it takes longer you have some buffer.
I like to finish mine with a short run in the electric oven at 500F ( 5 to 8 mins) to put a final crisp on it before service. If any bread or biscuits need to go in the oven is already hot.