I would like to add a smaller piece of advice on the first point:
Use a bright background
Instead just following this, I would suggest you either ask beforehand what type of screen and lighting you’ll have in the room, or even better, if possible, bring both a dark and a light version with you and ask for some time before the talk to do some testing.
The readability varies a lot with both the type of screen -LCD or projector? Matte or Glossy? If it’s a projector, how powerful is it?- and the illumination of the room -lots of variation there-. So, ideally, go for that second option of bringing both versions and having some preparation time before. And if this is not workable, do try to get as much information as possible so that you can, at least, try to simulate it to some extent.