Wanted to close the loop here and say thanks for your input, everyone!
Getting those birds in and smoked ended up being pretty hectic! I ended up going to Cabela's (my first experience with Cabela's, fwiw) and I picked up two metal poultry stands. I wasn't sure I would need them, but man I was glad I had them. I was going to go with Dave's over/under suggestion but it turns out they wouldn't fit! So I ended up using the stands and putting them on the same rack. It was dark, 6 in the morning, and I'm worried about time, struggling with 2 turkeys, jamming these contraptions in them, spilling stuffing, handling the birds with my welders gloves... but all's well that ends well. Everyone loved it!