#MFUKLC: Super Massive Hopper

I need a massive hopper to hold all the ping pong balls I intend to fire as part of the MFUKLC. I'm trying to maximize the material still so I've built up this frame work to hold 500+ balls. It's been made from 2mm mdf. I can use the extra 1mm of material in paper so I can skin the inside of the hopper to stop the balls from falling through the gaps.