I am planning to use this recipe on a 24 pound stuffed bird - I would be grateful for any guidance on cooking time that you could give. Many thanks.

don't stuff it , not worth the trouble. I always make the stuffing separate.

This advice may come too late for you if you've already purchased/ordered your big turkey, but I recommend roasting two smaller turkeys instead, especially for a stuffed bird. Here's why:
- Easier to handle
- Less chance of overcooking the turkey, especially the breast meat, when getting the stuffing up to the proper and safe temperature
- More pieces to go around! 4 legs, etc.

At 325F, a stuffed turkey of that size will need at least 5 1/2 hours or longer in the oven to reach the safe internal temperatures. To be honest, I'd hesitate to stuff and roast a bird that size. By the time the stuffing gets to the correct temperature, the breast meat will likely have dried out badly. There is also always the risk that not all of the stuffing will get hot enough, long enough, to kill off dangerous bacteria. I'd really recommend not stuffing a bird of that size, just because of the increased risks. Not to mention, the very long roasting time it requires. Also keep in mind that the longer your bird is in the oven, the less juicy and tougher it may end up being.