Looks pretty cool. I have a 1/4 20 bolt out the top of the vane that will thread in my weatherflow.
Just 1 bearing and 1/2" aluminum rod tampered to 10mm to fit the bearing . The vane slides on and off and I can push the rod in the ground and slide on the vane and it's ready to go.
This is the bearing I use
LR200NPPLR200NPP Track Single Row Ball Bearing Sealed 10x32x9 Track Bearings I took both seals off and cleared all the grease out of the bearing and now it moves very easy. I used double sided tape to hold the bearing in place, works great.
I'll try to post some pics of my build.