I had the same question about the thrust ring a few months ago when I built my first MPR model, the Estes Ventris. 
I've flown my Ventris a few times on Aerotech F24 reloads in a 24/40 case using a 24mm/29mm adapter from LOC Precision (All from hobbylinc.com)
Building it with a baffle is great, I use them in all my rockets, even the smallest ones, to eliminate the need for wadding. Less waste and faster preparation!
I've also used crepe paper streamers as wadding before, works well.
I like McKaila's Dad's idea of the tracking streamers! Never thought of that. Sounds fun!
I've flown my Ventris a few times on Aerotech F24 reloads in a 24/40 case using a 24mm/29mm adapter from LOC Precision (All from hobbylinc.com)Building it with a baffle is great, I use them in all my rockets, even the smallest ones, to eliminate the need for wadding. Less waste and faster preparation!
I've also used crepe paper streamers as wadding before, works well.
I like McKaila's Dad's idea of the tracking streamers! Never thought of that. Sounds fun!
