Personally for Fried Turkey, I simply Rub the bird down liberally with Salt Pepper and garlic and go to the oil. I've injected, rubbed, brined, etc... Never had a better turkey Deep Fried than the basics.
As for making multiples, I did three turkeys in one pot for Christmas one year. Just make sure your 2nd and 3rd turkeys do not collect moisture inside while waiting, give them another good pat in and out to get all the moisture off of them. It can get really messy when the oil has already been running at full temp for an hour and moisture exists.
Good luck. Enjoy.
3 - Brinkman Offset Smokers; 2 UDS' 1 w/Weber Lid and 1 with an Odd Lots Special Lid; 2 - Turkey Fryers; 2 - Gassers (Large and mini me); Maverick ET73
1- Cheap Charcoal grill (gone to the graveyard)