Any advice on how to get better at this? It's a traffic thing; if I slow way down far enough before an intersection I can generally time it but the occasional long red light has me wobbling and 'unclipping'.

Cranks horizontal, feathering the brakes, out of saddle - what else? Practice practice practice?

Thanks...

practice practice practice. practice on a slight uphill, for some reason it's easier. move your body around to find the center of gravity, this takes a while, but when you find it, it's like magic. relax, don't tense up.

Yes, yes, yes.

turn the wheel into the road crown, they are usually higher towards the center for drainage.

so the slope is an up/down , not as big a difference as the slope of a banked velodrome,

But that is what you have to work with on the street.