#1...DO NOT CALL IT "TRAINING".....no-one will show up.......LOL....We use a battery powered strobe light....either red or yellow (or both).....combine it with non-toxic smoke and it works well.....
We use our road/helicopter landing zone markers. They have red LED's in them and they can either flash or rotate. We set them in a place where we want to simulate fire, usually combined with theatrical smoke.