Let’s share our experience and help each other!
I use custom skydome and stationary skylight/directional light and when I change daytime I change skydome colours and skylight and directional light tint accordingly.
It does not give great effect, but it’s sort of plausible
Through, my method is pure bruteforcing, does anyone find better ways to do it?
I’m about the same thing, would love to hear what others have tried.
Directional light + Skylight + Atmospheric Fog = Sweetness 
Updating the skylight whenever the day time changes gives proper ambient lighting. I wouldnt call it dynamic GI but it is a good dynamic lighting solution nonetheless. It will be even better when Epic fixes the crashing issue with distance field AO.
That’s pretty much what I’ve been poking around with too. Works really well.