I am planning a trip to Dubai in about 3 weeks and my wife is accompanying me. I was wondering if anyone has experience J/S on either UA from IAD or DL from ATL?

My plan is to have her on a ZED and J/S myself. Where do I list for UA and DL and does anyone recommend one over the other?

Lastly, is there any problem with her being on ZED and me J/S? We have no problem taking whatever seats they offer and understand we may not be able to sit together so this isn't a problem. Reason I ask is once I J/S on Southwest with my wife on ZED and the agent told me it wasn't allowed. I had done it multiple times before but this particular agent wouldn't budge. I ended up sending my wife on the Southwest flight while I just J/S on another carrier to the same destination.