I am not totally sure of the situation you are describing but I mocked up an example model and with an example study in it. In this study the lectern is fixtured at the bottom to make sure there are no rigid body motions in the analysis. I then placed two split lines onto the left and right sides of the lectern where a speaker might place their hands. On this split line faces I applied the equivalent of an adult male as though they were applying all their weight to the structure in these locations.
Attached is the mock up. You may want to take a look through it is apply a similar setup to your own design.