That's basically exactly the solution I settled on.

Ahh excellent. I didn't even know that was a feature.
I might have a go at figuring out some circuit network wizardry to get the ore to distribute nicely between the wagons. I'll report back if I come up with anything I deem satisfactory.

I built this and after a while the final wagon in the rows gets clogged with ore and the system backs up and jams.
Did I miss something?