Moved to the night nappy section.
Have a look at some of the posts here, there's quite a bit of advice already.
It sounds like you really need to use a dedicate night nappy rather than a boosted day nappy. We use Flutterby Fluff night nappies (very hard to get hold of and you'll only be able to get them preloved now) , Puddlekins Silent Nights, Wee Notions Night Notions and Holdens Landings Bedbugs. If your LO is a heavy wetter I probably wouldn't get a bedbug though as they don't work well for everyone.