I was waking up every two hours to empty the bag and worried about leaks. Lack of sleep is a health hazard in many ways. Sleep is necessary and important.
One of my doctors came up with a solution for me. I use a two-piece bag. During the day, I use the regular-sized bag. At night, so I can sleep, I use the extra-large, high-output, urostomy bag. Your doctor can justify this for insurance purposes based on health risks from lack of sleep, the risk of depression, danger while driving sleep deprived, etc.
At this point, it only leaks when I go one day too long before changing it :) And then, I usually catch it before it is too messy and change it.
Over time, you will also develop a sense during the night for when you need to wake up and empty the bag. In the meantime, if you are concerned, when you go to bed, put a piece of paper towel around the area where it usually leaks to absorb it and prevent messes.
When I get worried during sleep, I put my finger on the skin barrier. If it is wet, I'll open my eyes and check it out. If dry, I keep sleeping. I'll also feel the bag to check how full it is. If very full or gassy, I will get up to empty it and go back to sleep.
I experimented a long time to find a system that works well for me. Each company will send 3-4 days of samples and complete sets of changes.
In my experience, some of the skin barrier flanges are so narrow, they do not hold at night while you are horizontal and the stool cannot as easily flow downward. I have found using a system with a wider flange helps enormously to prevent leaks. I use Convatec, Sur-fit Natura, Moldable, convex. Good luck, dear.