Mark
I used to run the dura hubs on my trailer. Did all of the east coast to Adelaide and back and the Cape and back. I found after a while the seal lips were cutting two nice grooves in the seal face of the stub axle. I also noticed when they were removed that the clear window in the front was cracked from the Cape trip.
Brilliant idea but it could do with some mods, the seal should run on stainless steel speedy sleeve reducing the grooving from the seal lips.
I used to run the durahub oil that you get with the kits.
Regards
Angus.