Help With Gear Raid 3-18

I have the other two gear raids to 18, and I'm able to clear up to gear raid 3-15 without assists. But I just need this one clear and have tried 100 times, and can't get it. Can someone outline the layout and hero's I should use? My main problem is that I don't do enough damage has the mobs come in and eventually overwhelm me. I have tried regearing my best gear onto team, have tried different teams. I have manned the wing platforms brought everything in, tried units like Dolores etc. Any advice is appreciated! Will add hero's as an edit.