Thanks for the suggestion here, I ordered the recommended clothes hanger rods for my truck and in theory, they would connect to the opposite support slots in the ceiling.
However you actually have to take off one of the rubber stoppers with hooks on them and fit it into the opposite slot and attach it to the rod with a screw and nut.
I removed the steel loops and used a screw and nut to replace them and make the install possible.
I have since ordered a Trxstle Telescopic Fly Rod tube to hang from these.
They’re working smoothly already. Here’s some pics for you,
Enjoy