Which do you think is a better idea, buying two slave flashes or one flash and a radio transmitter. (thats all i can really afford right now.) I'm leaning more towards the slaves because i get more light, especially if i can trip them both with the pop-up on my camera. If not, I would use one of them as a master/trigger in the hotshoe of my camera and the other off on a stand. Are radio's better?