I think the two biggest factors in transit time are probably time in stomach and time in pouch. Most of us have healthy stomachs, and the stomach is brilliant at storing food. Fatty food has a very strong effect, and tends to slow down the release of food from the stomach quite a bit. This is why peanut butter at bedtime helps some people sleep through the night.
Time in the pouch is most affected by how long your preferences and health cause you to wait to empty it. A healthy pouch can store contents for quite a while - folks who empty their pouch 4 times per day are waiting an average of 6 hours to empty, and I typically stay off the toilet 7-8 hours at night. Problems like pouchitis, though, can create urgency when even a small amount of poop enters the pouch.
If I eat fatty food at 6 PM I might not see some of it until 7 or 8 AM the next morning. The easiest food to see is, I think, peas, and lettuce is a close second for me.