Yeah it's hard to spread the light chaff. You can buy larger curved bats for the spreaders. And make sure you have them in the most aggressive set of holes, they're adjustable.

Here's some aftermarket bats that should spread chaff better, but I don't know how well they would hold up in corn. 
https://www.abilenemachine.com/parts/case-ih/category/straw-spreader-components/

Back in the day I've seen people go with a hydraulically driven chaff spreader that mounts below the straw spreaders, but I don't know if they are available the 5088 or not.