Lewis Jones claimed pole in an all-Symcirrus racing front row as he beat team-mate Lennon Docherty by 0.698secs with a lap of 2min 8.235s.
Chloe Jones will round out the front row on the third Symcirrus Kawasaki, just ahead of free practice leader Finn Smart-Weeden, as Ellis will start fifth.
HEL Performance British Junior Supersport with Motocourse, qualifying:
1. Lewis Jones (Symcirrus Motorsport) 2min 8.235s
2. Lennon Docherty (Symcirrus Motorsport) +0.698s
3. Chloe Jones (Symcirrus Motorsport) +0.147s
4. Finn Smart-Weeden (Wrapped Racing by Club 74) +0.891s
5. Joe Ellis (JPR) +1.323s