I used a NuVinci N380 and a bafang mid drive on my Kansas to Utah tour. It was great. I didn't use a throttle on the bafang. Instead I relied on its rotation sensor. The NuVinci allowed precise trim of speed and power draw.
My current build does not have on, simply because I don't have a spare NuVinci lying about. It will eventually get one.
This is a good article on the topic.