Well, I think I'll end up going with two batteries and two switches (simply because I want to have the option to only fire one).
I plan on using two 14500's (up to the right hand corner running vertically) in a 2x C battery box from madvapes... I know misterD is going to yell at me again when I say that, but I figure a 14500 still lasts a day of vaping (from what I've been told).
Sooo anyway, then I'm going to have a 10ml bottle (to the left of the batteries) with two tubes going up into the cartridge (I'm going to fashion a tip to use on the parellel attys coming up diagonally from the left corner). Then I'm going to have two LED's directly below the negative battery connectors, and two switches directly below each LED (which will end up being directly above the on/off switch located at the bottom right). I'll have to rewire the on/off with the new battery connectors (so the 14500's will fit). I'll run a negative wire from each connector to the on/off switch, and then each of those negative wires to their own atomizer connector. Each LED will have the ground leg to the negative connector conveniently located above them, and then a resistor connecting them to the switch prior to the atty connection (so they are on when the master switch is on). Then the positive wires simply from the connectors to the switch and then to the attys.
There is going to be A LOT of wire going all over the place because of the set up, but I'm hoping this thing works. After a brief convorsation with misterD I'm very confident it will all fit with relative ease.
What do you all think? I know this isn't revolutionarily new, but it's an idea I got into last night.
The only question I have is this: which switches from madvapes (I don't want to order from a bunch of different places for all the materials) should I use? They have to be smaller than the horn switches, and I don't want it to be one of the switches that you press and it stays down and you have to press it again to deactivate it. I want it to perform the same as the horn switch of just push and release, just smaller.
EDIT:
http://madvapes.3dcartstores.com/Push-Button-Switch--Red_p_2090.html would these switches work for the size?