Having done literally hundreds of videos of professional speakers on stage, you don't need the punch of a Joker to light this.
If you want a pretty even spread of illumination without a lot of hassle, set up a couple of Arri 650 FRESNELS at the back of the room in the corners so that the beams cross in the middle of the stage. Barn door them off to keep them from lighting the audience and the ceiling as this is unnecessary. That should give you enough general wide illumination to pull out eye sockets of actors and get a proper exposure with most cameras.
Fresnel lenses are the only technology that can essentially "throw" soft light from a small source to distance.
The rest of the calculation (is two enough or four too many?) relates to what's being filmed. Dark costumes on a dark background needing more light than a light subject against a neutral background, etc.