I have not done a 4-engine plane, but if I was about to start this is my thought process (actually I've been thinking lately about building a big scale DC-3 so this has sort of been in the back of my mind for the past few weeks).
First off, if you have some kind of failure you do not want both motors on one side of the plane to quit. So make sure you have both inboard motors powered off the same batteries, and both outboard motors powered off the other batteries.
My go-to motors are usually Hacker and E-flite. Both are very high quality motors with good product support. E-flite is a little less expensive, Hacker is a little higher performance with a little better technical assistance (as in calling from the flight line and getting someone on the phone who really knows these motors). Both of these motor brands can be run at their upper limits all day, every day, so there is no fear of pushing them and there is comfort in knowing you don't have to think much about something failing.
With 4 motors, I would probably divide overall weight by 4 and choose a motor for that size plane, i.e. choose motors for roughly a 4.5-5lb plane. This would bring you somewhere around an E-flite Power 25 or the Power 32. The Hacker A30 series is equivalent, just match the weight and kV. For me I'd think 3300mah would be a bare minimum, if not for anything else than the safety of longer flight time during the first few flights. I would weigh out the cost, desired flight time, and weight of battery packs (3S 3300 vs 3S 4000 vs 4S 3300, etc). I would decide on what power system I wanted, build the plane, then buy the batteries. This way you can get the biggest batteries you can afford (weight wise) for longer flight times and also not be stuck with bricks that are too heavy for your plane or that mess up the balance. I think my choice would be 3S packs and the Power 25 motors. It would cost less, likely weigh less, and be enough power. Higher mah packs will give longer flight times and run cooler, and cooler running packs last longer.
Here is a decent read to get started - it's geared toward electric twins, but same principle just double:
http://www.modelairplanenews.com/blo...win-electrics/
Here is an E-flite twin engine electric plane that is a little more than half the weight of what you're looking at. I would read the manual and basically copy the power system, X2 (meaning copy the way things are hooked up; copy the power system X2 if you decide on the Power 25 or 32, etc). You would get better performance though due to the weight, so the Power 25 would likely be fine. The manual should show you how to rig up your power system. Again, just double the wiring setup.
http://www.e-fliterc.com/Products/De...ProdID=EFL4550