I'm going to buy a second Spark and RC as a backup pair to the one I already have.  If both Sparks are paired to their separate RCs, do all I have to do to fly one or the other Spark is turn on the respective RC and look for it in my iPhone's available wifi's???  And will my DJI Go 4 Records build a new record for the new Spark???  There is no pairing of the iPhone to the Spark, is there...only to the RC???

The short answer is:  YES!  

Connect to the correct RC's wifi with your phone (or use the famous OTG cable) and off you go.  When you look in your flight records in DJI Go 4, you will see the pilot page, then 2 separate pages for each of your individual aircraft.  I'd recommend naming your different aircraft something unique or descriptive so you can easily tell the difference between them.

KlooGee Posted at 4-7 17:47
The short answer is:  YES!  

Connect to the correct RC's wifi with your phone (or use the famous OTG cable) and off you go.  When you look in your flight records in DJI Go 4, you will see the pilot page, then 2 separate pages for each of your individual aircraft.  I'd recommend naming your different aircraft something unique or descriptive so you can easily tell the difference between them.

Thanks, KlooGee!!!  Like you, I've never used an OTG cable...only one disconnect in 20 months.