I haven’t tried putting two Kayaks on the Lexus bars as I feel they are too short for that.
I sold my Thule Hull-A-Port J Bar carriers last week and I still have the Thule Dock Grip horizontal carrier that allows me to single-handedly load the Kayak from the rear.
When we moved the Kayaks a couple of weeks ago we made 2 trips.
Size (width) of your Kayaks is also a factor - mine are Hybrids so quite wide. Sea Kayaks are usually narrower than mine.
If I was younger I would wait for the Thule and carry two on the roof. Given how much higher than the UX the NX is, and the relative shortness of me and my wife, plus we are in our 60’s….. I am happy not to be lifting the Kayak into the J bar….