If you want to experiment just a little, try eating a small portion of applesauce with your lunch, or part of a banana to see if you can slow the afternoon output a bit. Just a few bites may be the key to start thickening things up in the afternoon.
Do you drink coffee or caffeine in the morning when you get up? From experience, that will make things speed up too. Some ostomates have to increase their sodium intake to help the dehydration. So a few salty pretzels, crackers, even chips are a good thing.
Please keep in touch and let me know what works for you.