I also used the Pampers Baby Dry Extra Protection diapers with my guy and was disappointed the first two nights. Then I came here on Mamapedia to read answers from other mamas and came across a couple of suggestions that worked, and yes, he slept 11 hours, sometimes a little longer, like you son.
1) Fold the top of the diaper down, front and back, before fastening, it worked like a charm to keep him from leaking, the only time he ever leaked along the top again was one night when I was ill and forgot to do it :(
2) Make sure you fan the diaper out completely all along the sides and bottom between his legs so as much area as possible is "open" for absorption.
3) I found this out by accident, go up a size in diapers. When I bought my second box of these diapers he had grown some so I bought the next size up. I was very pleasantly surprised to find they held even more, which makes sense as you have more area and material there to absorb.
4) And something I did with all my little ones to avoid constant sheet washing was have a few large waterproof pads to put one under them on top of the sheet, if they leaked I removed that to wash, and the sheet was fine. I learned that from my mother who raised 11 children, including a set of twins. She HAD to have tricks up her sleeve!
Last but not least, try the Kirkland (Costco) Supreme brand if you can, I ordered some samples right before he was potty trained, they were the absolute best diapers we ever used, had I known about them earlier they would have been the only diapers we used!!