Take some time after each session to think about it and share observations. To keep the discussion focused on suggestions, you can take turns with stating positive things from what you saw. After that, each participant can provide specific suggestions of what can be improved. Try to fill in the template "I suggest to...", and remind participants to stay positively focused at this. It's easier to accept feedback in this manner.
On a meta-level you should also think about things to change after each dojo. For example you can modify the switching time from five to six minutes, drop a rule or try something new in the next session. The group should make the decisions.
After the reflection, the team votes for the next facilitator, the time and place for the next dojo. The new facilitator becomes responsible to schedule and organize the next session.