Last week I tested a bambino large, two-ply. (inner diaper's panel sliced in several places) No boosters/stuffers, to see what it could take. Fitted leg cuffs very tight.
Drank a huge amount of water before bed, did not wet my diaper at all until I laid down. (and was pretty desperate) By morning I had dry sheets and removed a diaper weighing 7lb9oz, should have been about 3L of urine in there. I was very impressed. The padding was evenly saturated all throughout both diapers.
What's the best your diaper can do, without leaking? Be sure to tell your brand and size as well as amount.