I have a Alien B400 and I am thinking of purchasing a B800. I would like to use the B400 as a fill and the B800 as my main light. The fill light I have was a crappy ebay scam and in order to get a half decent result it has to be a mile away. There is not a slider to lower the power. Does the B400 automatically get triggered as a slave?(I hope that's not a stupid question). Would this type of set up work for large groups of people, like families with people situated standing and sitting? Thank you for your help.