I have a 22 on a tandem axle trailer with bearing buddies. I dd put in new Timken bearings/Kodiak brakes etc. (never used it with the old stuff, so can't compare).
I'd say the bearings tend to run around 15º - 30º over ambient temp (so say, 95º on a 70º day or 110º if it's 95º outside). The variation between hubs might be around 5º or so. I am careful to tow with the trailer level since it is a tandem; measurements are made with an IR thermometer just after pulling in to a rest or fuel stop.
A note is that when I first had the work done on my trailer, there were (as it turned out) quite a few flaws in the work. I was getting really high bearing temps (180º - 200º +). Of course when I called the shop that had done the work they said that was normal and I was a worry-wart. As it turned out, the castle nuts were too tight, some of the brake shoes were dragging on the hub, one of them was crooked and half worn down, the brakes were sticking due to a kink in the line (that I had pointed out but they'd said not to meddle) etc. etc. Got all that straightened out (in the middle of Georgia, the middle of Montana, etc.) on my first cross-country trip, and right away the bearing temps went down to "nice and cool" and have stayed that way over many thousands of miles.
PS: I don't tend to tow "stop-and go," so can't speak to that specifically. OTOH, I might pull into a town and drive 2-3 miles through surface streets, and I haven't really noticed a big difference then after stopping.