Test your slides at 800x600 or better yet 640x480. (Live stream is usually 320x240 => i.e ~1Mbps)
- Also use this resolution for live demos.
- If possible, use your mouse pointer rather than your hand or laser pointer to point out things on the screen, so the VGA grabber captures what you're pointing at. It may be useful to configure a larger pointer beforehand.
- As a rule of thumb, use a fontsize like 32pt for normal text. For slides prepared at 800x600, 24pt will do quite nicely, if the contrast is good and the fonts are quite fat. However, presenters will likely have 1024x768 or bigger screens on their laptop, so 32pt will be closer to the sweet spot.
- DO NOT point the microphones at the speakers when near them (feedback will occur!).