I'm not sure why you want to absorb impacts (i.e. keep the balls from breaking)
I used two sections of large diameter PVC Pipe and an Elbow, glued with PVC Glue. All of this tied down to a wooden stool I had.
First secion angled slightly downward so that the ball hits the tube at an angle and cracks while the spray and surviving fragments hit the elbow, then drip down the second section and into a bucket. If you're angle is good enough, and the tube length long enough, nothing will come back out. Here's a video of it sucking up a 100rd rope of full auto, and not a single drop came back at me:
With whatever design you go with, you want either disposable, or easily cleanable, anything between is a pain.