Any current videos on how to win Quad defense?

[bz_siege_01]

I've beaten triple, but quad is driving me crazy. To be fair, I reset the game and unlocked very few towers so that I have higher card-draw odds of leveling the ballistas and poison sprayers up. I have died at level 41 twice. It seems like no matter how I position and prioritize, I can't do enough damage at the beginning of each lane to prevent those guys from launching the high-armor missiles when they die. I always seem to have a wave where all the missiles are making it to my tower and I go from 30+ health to nothing. And yes, RNG plays a huge role, but there has to be strategies to focus on that will be optimal when RNG doesn't screw it up. So... are there any videos out there of someone beating quad defense? I've found a few older pre-release ones with different balance to the game. One showed just ballista and poison sprayer with some university upgrades, which I've used to get to 41. But there must be a better way.