We did a deep fried turkey as well, makes dry turkey a thing of the past. Used a homemade brine of 1 cup of kosher salt, 1/2 cup brown sugar to one gallon of water. Mix well until salt and sugar is dissolved. Put turkey in container large enough to hold it and the brine. The turkey should be under the brine completely. It was cold enough here that we sat the turkey outside overnight as no room in the refrigerator, was still covered with ice cubes in the morning....I put ice on top to be sure it would stay cold. In the morning remove turkey from the brine, pat dry with a towel. We used a creole butter sauce injected under the skin of the bird in several places. Sounds spicy? No it just gives great flavor to the turkey. To judge how much oil your turkey fryer needs put the turkey in the frying container, cover with plain water. Mark the line at top of the water. Remove the turkey. Empty the fryer and dry it out. Fill with peanut oil to the mark. Heat the oil to 375 degrees. Our fowl needed 45 minutes to cook at that temp. Be sure turkey is patted dry again prior to cooking as oil and water is not a good combination.
Our turkey fryer was a Christmas gift a few years back and it gets a lot of use. The average 10-12 pound bird requires about 4-5 gallons of peanut oil. It can be strained after it cools and returned to the oil bottle, reused a few times but if it gets too crusty in bottom or you cook fish discard the oil and buy new. The 375 degree temp causes the skin to be seared right away sealing in the juices which is what makes the bird so moist.