Add some cables and a few ground rods to strengthen your poles, place 2 more taller poles maybe 10' in front of the 2 at the plate, offset alittle, and you could add some netting over the plate. Would stop the pop ups and foul balls from going behind the net. We made a couple of batting cages in a post barn, 50'×30, got our netting from a batting facility that had closed down.
Our old rec league just got 2 of these to setup outside. Pretty nice but the had to supply their own pipe in between the corners which they didn't expect to do.
Thought I would share this story to prevent others from make the same mistake I did. When my DD started playing 10U TB our basement was not finished, so I built a batting cage down there. It was not full sized, but just long enough for us to pitch (35') and do front toss. I did not have an L-screen and did not want to pay a lot of money for one, so I went to Home Depot and bought some PVC pipe and fittings, a bag of playground sand, and some landscape fabric (@ $25). I put it all together and was very proud of my creativity - I even spray painted the PVC piping black. Needless to say the first hard line drive my DD hit went right through the landscape fabric and just missed my head. BP over, back to Ebay to find a good deal on an L-screen net. PVC pipe held up pretty well, but it broke a few times through the years. Used PVC couplers for repairs.
1" golf cage frame on Amazon for $104...you use 1" EMT piping for the framing to hold up the net. I will corner brace all of the corners, since a softball has a little more force than a golf ball.