Tried it again and yes, it was as easy as reversing the ends. In fact one end has 'Host' written on it.
It will connect with wifi turned off. Just waiting for a decent day to try it out.
Should I be seeing better streaming video as well, or simply longer range?
Should be better video.
Some say it helps with range, I don't think it does.
But it might?
The therory I read was that the processing power of the remote is concentrated on the Spark transmission and not two WiFi signals. (Device and the Spark).
With using the cable, it eliminates one of the WiFi connections that the remote has to use and concentrate it's power on the Spark transmission.
It seems that the rest of DJI's fleet uses a cable, so should the Spark.
It was a fluke that somebody stumbled upon when the Spark was released in 2017, and DJI was back and forth on the support between Android and iOS devices.
More user friendly with Apple, not so much with the Droids.
That was then, this is now and the cable is the way to go.
If you want better range, an inexpensive pair of parabolic reflectors that slip over the remote antennas work well as they concentrate the signal to and from the Spark.
Just be sure to point at the Spark at all times.
With a concentrated signal, you might lose it if you spin yourself around 180* to talk to your buddies or another distraction.