It does typically take about 5-6 hours for them to show up. I know eBay is working on some things to try and shrink that again. They used to have it at about 1 hour a few years ago. But as they started combating fraud more it takes longer. I think their servers are capable of getting them into search within 1 hour still but it's mainly the checks for fraud that is keeping it closer to 6 hours for now.
Your listings should end normally at the time you started them at. So you have to ask is it more important that they be visible at your start time or your end time, then schedule based on that. I think end time is more important so that means you're stuck listing them when you do and losing that initial 6 hours of visibility in search.