I find that the whole tends to be less than the sum of the parts with disposable double-diapering. For me at least, the two nappies just seem to interfere with each other and make leaks more likely.
For me the answer has been heavier nappies augmented with plastic pants.
The more you post and the more you comment the system updates you to different levels. I think the top tier is Diaper Royalty. As that is what @DailyDi is and he has been here the longest as he created this website.