My doctors tell me that the longer the emema retained, the better. I often can retain at least 8 hours (10PM - 8AM).
Thats' pretty impressive: retaining an enema 8 hours! You must have super strength sphincter muscles - lol.
Back when I was using enemas, which didn't work, my best retention time was 15 minutes, and then I would feel like I would explode.
With the suppositories, my retention time is about 8-10 hours.
I think you're doing great.