I end up rebuilding all my hubs with Timkens. As mentioned, I got a brand new trailer with a bad hub. Personally, I think it was bad assembly, and the person putting the hubs on did not know how to set/adjust them. Talking with the company, they ONLY sell pre-assembled hubs with minimal grease. When I asked the rep "How does someone go about adding/packing grease in a hub with a grease seal installed", he didn't know. It was a rhetorical question but I had to ask. I went ahead and just hammered out the races on the old hub and replaced with all Timken.
I just did a set of Timkens in my trailer. Adjusted them, greased them, and proceeded to pull the boat 200 round trip miles going 65mph or more. I stopped once on the way and once coming back to see if they were heating up. Cool as the other side of the pillow.
I probably don't trailer nearly as much as @tod osier but I am a fanatic about trailer safety. I had to help someone out with a hub that went bad on the road and it was NOT fun.
I have no experience rebuilding a hub on the side of the road and I'd like to keep it that way.
It sounds like from what the 2 of you are saying, I'd want to consider wheel/tire upgrades if I was on wheels less than 12". I just ordered some 12" radials that hopefully will behave.
When I'm trailering, I always put my hand on the hubs when I stop to get gas to check temperature. Next fair weather spell we get, I'll pull things apart and repack.