I'm new to continuing video lighting. My only experience is on camera video light.

My typical academic seminar video shooting is deploying the Panasonic DVX100B 50 feet away from the podium, inside a hotel function room (sitting 200 attendees) without windows and extra spot lights. Next to the podium is one big screen for Power Point presentation. The ceiling lighting of the hotel function room usually dimmed down for 200 attendees to read the slides on big screen clearly. As a result, the speakers’ faces normally looked dark in the video despites the DVX100b’s low light performance is not bad.

Now, can I prepare two continuing lightings facing the podium at the back row of the room to add some light on the speakers without distributing the contra of Power Point presentation? Any less expensive non-heat continue lighting system (2 units) suggested ? Each shooting session is 5 hours and two seesions in a day. The light must be able to switch for 10 hours.

My next question is how to calculate the required power of lighting, in terms of distance and color temperature? ? Is there any equation or web site to learn from ?