This video shows the sound from a special custom string gauging to make a banjitar sound more banjo-like. String gauges used are (in order of EADGBE) 010, 013, 017, 13, 17, 10. The top three strings are tuned an octave higher than normal.
Over the last few years, since this video was made, I started using these strings. They sound amazing! (Amazon link) https://amzn.to/3XbH17R