Yeah, EZ cushion is great, you can feed hands free. If not, you can use a variety of cushions pillows, but try to make the top surface as flat as poss so they dpon't roll off easily, then you can let go.
Have you tried the 'baby-grow grab'? It's the safest way to pick up a baby with one hand. Lie baby on back, grab baby-grow under the chin and lift gently, baby-grow supports the back of baby's neck. You can use this to carry both, or move one at a time onto feeding cushion. If you want to take them upstairs or something, grab baby-grow as above, then move arm round so baby's back is resting on your shoulder/chest facing forward, do the same with other. It's much safer picking babies up like this as if you 'scoop' them they can rool off.
To tandem feed on your own. Get everything you need within easy reach: drink, snack, remote control. Place babies on bed or sofa next to you, arrange cushion/s grab baby 1 by baby-grow, place on cushion, grab baby 2 by baby-grow, place on cushion, latch baby 1, latch baby 2
Good luck with it, you're doing brilliantly :-)