The dry run idea is really smart. We've done something similar, where we had Niv Dayan[1] lead a session on Diva[2] (before it won Best Paper at VLDB 2025!). I had worked with him in the past and thought it would be cool to have him present to the group. Having the author in the room completely changed the quality of the discussion. Most of our sessions right now aren't presenter-led, but I'd like to do more of that.
[1] https://scholar.google.com/citations?user=vdMOvmIAAAAJ [2] https://www.vldb.org/pvldb/vol18/p3923-eslami.pdf