This is a picture of my 3000 gallon steel tank that I use for a chipbox. At the time we were covering the tank in vinyl siding so I wouldn't have to paint the exterior every few years. You can see the 4" PVC inlet on the end of the box, its below the top edge just enough so the chips and dust settle in the tank. I have never seen any dust or chips on the grass around the tank even though it does not have a top, its completely open. Currently the tank is about one third full. There is a one inch pipe at the end of the tank near the bottom. I shoved a piece of carpet foam inside the pipe so the water can drain out when it rains and chips stay inside.
My dust collector is a very old Grizzly 1.5HP model that originally used bags. I removed the DC vac and discarded the metal cart, the bags and all of the other hardware, the vac now sits directly on the concrete floor in the corner of my shop. I can't find a picture of the vac, I rarely see it anymore because it generally blocked by other machines I park in front of it at the end of my panel saw.
Without the bags the performance of the little 1.5HP vac has increased significantly.
I used a similar setup for the sign shop at Christopher Newport University. I purchased a Harbor Freight 2HP collector, scrapped the bags and installed the vac very close to the back wall of the shop. On the opposite side of the wall just outside I used the original shipping box that the ShopBot CNC Router came in, just painted it white and installed a vent at the opposite end of the inlet. I had to use the top on the box because it was small and located just a few feet from a walkway that students used to get to the main campus from a large parking lot. I stapled a baby diaper inside the box over the dryer vent. This system worked great for several years while I was employed by the University and it still being used today.
Don't make rocket science out of a chip box installation, keep it simple and it will work just fine.