I raised really large turkeys, some of the BBWs were about 80 pounds on foot. It took the tractor to lift them! We lifted them as high as we could, so when I cut the throat, I could duck and get out of the way, before he started flapping his wings. If you don't have a tractor, you could install a pulley onto a tree and use a rope to lift him and tie the rope off at the desired height.
We now raise White Hollands, which max out over 40 #, some over 50#. I didn't weigh them before processing, but after, they dressed out at 34 to 35 #s not counting giblets. We do not have a whizzbang and don't think it would fit, anyway, but if you try, make sure you pluck the large tail feathers and wing feathers, and you might have a chance with a plucker. After the turkey is bled out, we gently lower it into a very large seafood boiling pot, while still hanging from the tractor and into 155 degree water. Hotter water will tare the skin while plucking and cooler water makes plucking a lot harder. We plunge it into the water and count to 10, pull it up and try the wing and tail feathers, if loose enough to come out easily, it ready, if not lower it back in for another 10 count and repeat. The feathers should come out quite easily. It is not much work plucking only 2 or 3 at a time, by hand! Since there are so many squeamish people who read these threads and should realize processing fowl is not like petting a kitty, but will complain at seeing a dead bird, I will send you some pictures of the White Hollands we processed last Thanksgiving in a pm! Hope this helps.