Be nice. Or else.
Thank you sir!
Asking them about the kind of feedback they want is an interesting move, it might give them a little bit of the power in the situation. Perhaps that helps their confidence and likely improves the quality of the conversation/debate, if they think you're truly invested in giving them the feedback that's most beneficial to them. Psychological safety seems important for the free exchange of ideas.
I think it's really important that you consider each person carefully, and that you've taken the time to acknowledge and learn their feedback preferences.
Keep up the good work -- pidä lippu korkealla!