https://banjobenclark.com/lessons/how-to-play-banjo-harmony-banjo-advanced
There’s making music together, and THEN there’s playing banjo harmony together! Banjo harmonies, or twin banjos, aren’t super common (in fact, I think it’s illegal in some states), but it’s a challenge and I think pretty doggone cool!
Looks like 6 weeks of 2 hours a day…. But would be worth it! Good lesson Ben! That is such a cool sound but to actually USE it in a jam would be more than awesome!
BHarmony dot com. Ha! 
Loved it! Some of those riffs had similarities to your arrangement of In the Sweet By and By. Yes?
Probably so, lol. I’m sure I have a lot of patterns and habits.