The knot surgeons use in sutures is a variation on the strangle knot. The first overhand goes over a second timean be snugged up or tightened as you wish then tie a regular over hand knot over it and then another again. I like to use a square knot over the intial multi wrap overhand, it makes it easier to take out. Surgeons don't care about taking out their knots they just cut them.
As a liciensee of the California Dept of Insurane I have placed craft fair insurance. There are several companies who write insurance for events onnly and you pay in advance of the event per event. Ask you local insurance Agent and if the agent doesn't know ask another.
It sounds like a fascinating conference and it appears you had a great time! I enjoy conferences for the people you meet and the exchange of informaiton that occurs.